Best to revisit each trader after you level up because they restock after your hero level up
Some chest have a fixed LEVEL, but with equipemnt/weapons with RANDOM boosts, some content in a chest level up with your hero's level (till a certain level I think) ... etc etc....
So not all gear you find in chests will have the same level of your hero.
The same with "loot" dropped by enemies ... fixed, random or a combination of both ...
