The Mine a Planet drill inventory lets you carry multiple drills and switch between them at any time, which is essential for end-game players who want to use different drills for different planets or farming routes. The default inventory holds 12 drills, but the Epic Pet Slot item doubles that to 24. This guide covers the inventory mechanics, how to swap drills quickly, and the optimal drill loadout for end-game players.
For the broader inventory management strategy, see our Mine a Planet fast Drill Piece farming guide. For reforge strategy across multiple drills, see our Mine a Planet reforge strategy guide. This principle applies broadly across all progression stages and is one of the most reliable optimization levers in the game.
Inventory Slot Mechanics
Every Mine a Planet account starts with 12 drill inventory slots. Each slot holds one drill, and the drills persist across sessions and rebirths. You can swap drills by opening the inventory panel and clicking the drill you want to equip, or by using the keyboard shortcut bound to the drill slot.
The inventory does not reset on rebirth, which means your drill collection persists indefinitely. This is useful for end-game players who want to maintain a collection of reforged drills across multiple play sessions and rebirth cycles. The exact mechanics vary slightly by patch, but the underlying principle remains consistent across all player playstyles.
| Inventory State | Default Slots | With Epic Pet Slot |
|---|---|---|
| New account | 12 slots | 24 slots |
| Mid-game | 12 slots | 24 slots |
| End-game | 12 slots | 24 slots |
How to Equip a Drill
Equipping a drill is a simple two-click process. Open the inventory panel by clicking the bag icon in the top-right of the screen, click the drill you want to equip, and confirm the swap. The previously equipped drill returns to its inventory slot automatically.
For faster swapping, the developers have added keyboard shortcuts that let you bind drills to number keys 1-9 on your keyboard. Press the corresponding number key to instantly swap to the bound drill without opening the inventory panel. Most end-game players bind their most-used drills to keys 1-3 for instant access.
| Method | Speed | Best For |
|---|---|---|
| Click in inventory | 2-3 seconds | Casual players |
| Keyboard shortcut | less than 1 second | End-game players |
| Auto-equip on craft | Instant | New craft pickup |
The Epic Pet Slot Inventory Doubler
The Epic Pet Slot is a consumable item that doubles your drill inventory from 12 to 24 slots. The item is purchased from the in-game shop for 500 Robux or earned through limited-time events. Once purchased, the Epic Pet Slot is a permanent account upgrade that persists across all sessions and rebirths.
Most end-game players consider the Epic Pet Slot a worthwhile investment because the doubled inventory lets them maintain a full collection of reforged drills for every planet and every farming route. Without the Epic Pet Slot, you are limited to 12 drills, which is enough for one drill per tier but not enough to maintain separate reforge variants for different use cases.
Recommended Drill Loadout for End-Game Players
The optimal drill loadout for end-game players is one drill per tier, plus backup reforge variants for the most-used drills. A typical loadout might include the Astral Annihilator (main), the Cosmic Reaper (backup), the Mythril Destroyer (third tier), and several reforge variants of each.
| Slot | Drill | Use Case |
|---|---|---|
| 1 | Astral Annihilator (perfect reforge) | Main end-game drill |
| 2 | Cosmic Reaper (high Ore Multiplier) | Backup for Cosmic farming |
| 3 | Mythril Destroyer (high Rare Drop) | Low-tier content and chests |
| 4 | Astral Annihilator (alternate reforge) | Trade experiments |
| 5-12 | Reforge experiments and trade stock | Various |
This loadout gives you instant access to the right drill for every farming route without inventory juggling. The Epic Pet Slot expansion lets you carry additional drills beyond this core loadout. Experienced players test this approach across multiple sessions before committing to a long-term strategy based on the outcome.
How to Manage Drill Inventory Overflow
If you find yourself running out of inventory slots, the best approach is to sell unused drills on the trade market rather than letting them accumulate. Drills at every tier are tradeable, and even Common-tier drills have meaningful market value for new players.
The second approach is to salvage drills for materials. The Salvage Station accepts unwanted drills and converts them into Drill Pieces based on the tier. A Mythril Destroyer salvage returns roughly 1-2 million Drill Pieces, which is meaningful refund value.
| Drill Tier | Salvage Value | Trade Value |
|---|---|---|
| Common | 100-500 | 500-5,000 |
| Rare | 1,000-10,000 | 5,000-100,000 |
| Epic | 10,000-100,000 | 50,000-500,000 |
| Legendary | 100,000-1,000,000 | 500,000-10,000,000 |
For most players, salvaging is a better choice than trading because it gives you immediate Drill Piece liquidity. Trade is better for players who want to participate in the trade market or who need specific drill variants they cannot craft themselves.
Drill Slot Configuration by Progression Stage
The optimal drill slot configuration changes as you progress through the game. In the early game, the best config is two empty slots plus your active drill, because you do not yet have enough high-tier drills to fill the slots. In the mid game, the best config is active drill plus your two highest-tier drills, which gives you instant swap access without re-equipping. In the late game, the best config is one active drill plus three situational drills (one for raw ore, one for rare drops, one for boss nodes), which lets you adapt to any farming scenario within seconds.
Switching slots costs roughly 2-3 seconds of in-game time, which is meaningful during fast-paced farming sessions. Players who keep all their drills in their inventory and manually swap them out lose roughly 10-15% of their potential farming throughput compared to players who use the slot system efficiently.
Drill Slot Unlocks and Costs
The drill slot system unlocks in stages, with each new slot costing progressively more. Slot 2 (the first extra slot) unlocks at player level 15 and costs 5,000 Drill Pieces. Slot 3 unlocks at player level 30 and costs 25,000 Drill Pieces. Slot 4 unlocks at player level 50 and costs 100,000 Drill Pieces. The total cost to fully unlock all slots is 130,000 Drill Pieces, which is a meaningful but not prohibitive investment.
Players who are Drill Piece-constrained should prioritize the Slot 2 unlock first, because it is the cheapest and gives you the most immediate value. For more on Drill Piece farming, see our fast drill piece farming guide, which covers the optimal grind for each player level range.
Frequently Asked Questions
Can I expand my drill inventory beyond 24 slots?
No, the Epic Pet Slot doubles the inventory to 24 slots, but there is no further expansion beyond that. Players who need more than 24 drills must use the salvage station to clear slots. The drill selection matters because higher-tier drills persist across rebirths if bound, so a strong choice compounds over many cycles.
Do reforged drills consume inventory slots?
Yes, each reforged drill consumes one inventory slot, even if it is a duplicate of the same drill tier. This is why the Epic Pet Slot is so valuable for end-game players who run multiple reforge experiments. Save high-tier reforges for drills you intend to keep across rebirths, since reforges persist on bound drills and compound over time.
Can I have two Astral Annihilators in my inventory?
Yes, you can carry multiple Astral Annihilators with different reforge stats. Most end-game players keep 2-3 reforge variants for different use cases. Yes, but the optimal approach depends on your current progression stage and your stockpile of supporting materials. Combining this insight with active pet bonuses and prestige multipliers yields compounding benefits that accelerate overall progression.
What happens to my drill inventory when I rebirth?
The drill inventory persists across rebirths, but the bound drill is highlighted at the top of the panel. Unbound drills remain in their slots but cannot be equipped during the rebirth tutorial phase. The exact behavior depends on the system in question, but generally the game preserves your cumulative bonuses while resetting current resources.
Is the Epic Pet Slot worth 500 Robux?
For end-game players who run multiple reforge experiments, the Epic Pet Slot is worth it. The doubled inventory lets you maintain a full loadout of reforge variants, which provides meaningful gameplay flexibility. Yes, this item is valuable at every stage because it provides a permanent bonus that compounds with other systems.
How to Organize Your Drill Inventory Effectively
A common mistake is to organize drills by craft order rather than by use case. End-game players should organize by use case instead — main drill on slot 1, backup drills for specific routes on slots 2-4, reforge experiments on slots 5-8, and trade stock on slots 9-12.
| Slot Range | Purpose |
|---|---|
| 1-3 | Main drills for active use |
| 4-6 | Backup drills for specific planets |
| 7-9 | Reforge experiments |
| 10-12 | Trade stock and future projects |
With the Epic Pet Slot expansion, you can extend this organization to 24 slots, which is enough room for two full sets of reforge variants and trade stock. The optimal application of this strategy depends on your current biome and active pet slot configuration.
Keyboard Shortcuts for Fast Drill Swapping
The keyboard shortcut system lets you bind drills to number keys for instant swapping. To set up shortcuts, open the inventory panel, hover over a drill, and press the number key you want to bind it to. The drill is now bound to that key for the duration of the session.
For long sessions, the keyboard bindings reset when you log out, which means you have to rebind your drills each session. This is a minor inconvenience but it does not significantly slow down your gameplay. Most end-game players rebind their 3-4 main drills at the start of each session and rarely swap afterward.
Common Drill Inventory Mistakes
The most common mistake is to fill the inventory with sub-optimal reforges that you never use. Instead, salvage or sell drills that do not meet your use-case criteria. A clean inventory with 5-6 perfectly rolled drills is more valuable than a cluttered inventory with 12 mediocre drills.
The second mistake is to leave your main drill bound across a rebirth when a higher-tier drill is available. Always bind the highest-tier drill available, even if it means sacrificing a reforged variant for a stock higher-tier drill. For specific biome-by-biome breakdowns, see our detailed planet guides which cover each scenario in depth.
The third mistake is to over-rely on trade purchases. While buying drills from the trade market is convenient, the long-term cost of buying drills exceeds the cost of crafting them. Most players should craft their own drills and only buy from the trade market when they need a specific reforge variant.
Drill Inventory During Active Crafting Sessions
During active crafting sessions, the inventory fills up quickly because every craft produces a new drill. A typical crafting session might involve crafting the Iron Hammer, the Titanium Spire, and the Mythril Destroyer in sequence, which fills 3 of the 12 default slots.
To manage this, end-game players either: (1) keep an empty slot reserved for new crafts, (2) salvage unwanted drills immediately, or (3) use the Epic Pet Slot to expand the inventory. The first approach is the simplest and works well for players who craft less often.
What Happens When Your Inventory Is Full
When your drill inventory is full and you craft a new drill, the new drill is automatically placed in your overflow queue. You can either equip the overflow drill immediately (replacing your currently equipped drill), send it to a different slot (if available), or salvage it for Drill Pieces.
There is no warning when the inventory is full, which means new players sometimes lose access to a freshly crafted drill because they did not realize it was sent to overflow. The best practice is to check the overflow queue every time you craft a new drill.
Sharing Drill Inventory Across Multiple Accounts
Drill inventory is per-account, which means drills do not transfer between Roblox accounts. If you have multiple accounts, each one has its own separate drill inventory, reforge history, and Prestige Shop progress. There is no cross-account trading or inventory sharing.
For players who run multiple accounts, the practical implication is that each account must be progressed independently. There is no shortcut via inventory sharing, which means alt accounts require the same time investment as the main account. Veteran players typically learn to recognize these patterns within the first 10-15 hours of focused play.