Borderlands 4 from Gearbox Software and 2K makes inventory management important because players quickly collect more weapons than they can carry. This brief guide demonstrates how to optimize inventory space using the in-game SDU system and explains why upgrading the Backpack is crucial for extended runs and more challenging fights.
Borderlands 4 stores its upgrades in the SDU menu, where Backpack upgrades directly increase the number of items a character can carry. Each Backpack purchase increases capacity, and prices rise as levels go up, so progression matters. SDU is awarded through regular play: completing activities, claiming safe houses, and clearing Order Silos all grant the currency needed. Players short on space should prioritise Backpack upgrades before niche quality-of-life purchases.
Apart from carrying capacity, the SDU menu also upgrades ammo reserves, allowing players to store more rounds for each weapon type. The Lost Loot option increases how much lost loot is retrieved after a mission, which helps players who skip post-mission sorting. It’s not always the best Borderlands 4 legendary weapons that appear, but a bigger backpack keeps options open. That extra room is handy when facing tough Borderlands 4 bosses or when swapping builds mid-run.
Progression ties everything together: more activity, more SDU, more upgrades. Always prioritize Backpack levels first, then ammo and Lost Loot upgrades to keep runs smoother and less interrupted.
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