There's 2 styles I'd like to see and they're both different depending on whether it's your armor or weapon.
Armor: Is always going to need to be repaired or replaced from constantly taking the hits the skin isn't. Buckles, straps, etc. are going to become loose, and if left unattended they're going to snap or break, causing the piece it's holding on to become dangerously loose. Then there is the generally state of the metal or leather. Leather would no to be sewn back together where it has been punctured or that segment replaced. Metal would be reforged or replaced. The prior would be mostly time based or wear-and-tear, the latter, or "big" damage, would be sudden and related to critical hits. If you're hit by a giant enough times, your metal armor is going to be dented. Would prefer it to be verbal warnings, so "left should strap is loose, very loose, broken", having multiple stages and "chest protecter is broken".
Sword: Similar to armor it'd have small damage and large damage, wear-and-tare vs. traumatic encounter. Swords get dull and chipped the more you use them, unless it's made of Mithril, Adamantium, Valyrian steel alloy: very sharp, sharp, dull, very dull, large butter knife . Then there is the big damage like a broken cross guard, it's bent, etc.
The small damage for armor and weapons could be fixed in the field so you don't have to go to a blacksmith. Sew-up buckles, fix straps, etc. with a small kit and use a whetstone on your sword. If it's a big damage, that's when you take it to a smith. Weapons and armor would still be usable when they've taken big damage, but their effectiveness would be considerably downgraded.
*Aware I didn't go over the crossbow, but I'm lazy and it wasn't in the previous versions so I don't know exactly how it'll be implemented.