Survival rewards
Farm Survival waves for armor
Use later Survival waves on a map you can clear to collect armor and other map-specific rewards.
Survival on any map whose campaign you have cleared at the chosen difficulty.
Repeat Survival for more drops. Armor pieces and their attributes vary, and clearing the campaign unlocks Survival for that map and difficulty.
Stop when you have armor that improves your build or when the next wave risks the run without a worthwhile target reward.
Open a guide to find other locations and see what the item is used for.
Use later Survival waves on a map you can clear to collect armor and other map-specific rewards.