Some characters enjoy using their downtime to craft mundane items. Repairing your armor, making some new arrows, concoct a potion of healing or whipping up a tanglefoot bag.
D&D is notorious for making the crafting rules complex or unusable for adventurers. I am talking about crafting mundane items, not magical ones. Let’s take a look at the rules for D&D 3.5 and 5th edition, and my suggestions for changing them.