I believe you are new to the game so you are generation 1 and didnt retire yet right?
If yes, some infos for you:
Until you reach level 25 for the first time in the game, you do not have to repair any of your items. BUT when you have reached level 25, you will repair alomst every round at least 1 item.
If you are using a bow, crossbow or throwing weapon, the percentage of possible upkeep will increase, when you do not have alot of Weapon points in the fitting types of wpf.
As you are a beginner, I would rather take more cheap weapons and armor instead of very expensive ones.