Quick answer
Treat empty grid cells as a resource. The inventory is diegetic rather than a pause-screen abstraction, so reorganize in a secure place and keep enough flexible space to accept an unknown tool or supply.
A practical packing order
- Progression tools: retain them until a route or patch note clearly establishes that they are optional later.
- Loaded weapon and ammunition: verify the magazine state manually rather than assuming an on-screen counter exists.
- Medical or food supplies: carry enough for the planned route, not every item in storage.
- Flexible gap: preserve a shape that can accept more than one kind of pickup.
Before leaving a safe area, ask which item solves a likely blocker and which item merely duplicates a capability.
Backpack update warning
Version 1.03 changed backpack pickups so only actual upgrades can be collected, addressing duplicate inventory items. An older guide or save may describe behavior that no longer occurs. Update before troubleshooting apparent duplication.
The community guide confirms the broad player workflow but is not used here for an exact slot count, item dimensions, or a universal optimal layout. Those details should be checked in the current version and can vary with acquired upgrades.