Cloth has specific lifetime?

Hello everyone, I'm new of SSO, Italian on Thailand Athena server cause probably Perfect World won't decide to release an UE server.
Lvl 70 and got some clothes... I liked the many guides here about so many topics (I miss wings cause of my nab) but I haven't found anything detailed about clothes stats and char windows, like "sense", "cons" and "ranking". Anyway my main question regarding the fact I've just upgraded my bronze Phoenix cloth to 17/48 and I've played with it for PvP and some dungeons. I started to notice that there's a particular stat below (white text) that at the beginning displayed 576/576 but now after using it shows 568/576: is there a way to fix clothes or I miss something I don't know? Or every cloth has a specific lifetime of using after that will disappear and you have to get it again? O_o
I tried to get if there's something to do or use some items but I can't find anything useful.

Thanks in advance

p.s.
I think this is a great game, I played Aion of NCsoft for 4 years and get bored of wasting money on it without the possibility to get better for sure. I hope one day there will be an NA or UE servers for SSO too

just repair your equipment in any vendor npc . If that number reaches 0 your equipment will break. but you can repair it.repair your equipment everyday because it will cost more money repair a broken equipment

Thanks mauricarus very kind :-) Now I'm lvl 77 with 2 gold clothes ... Pisces and Leo, still 72000 pwr lvl about. I saw a lvl 79 with 150k pwr lvl and 350k HP ... all items upgraded and Fire spirit x6 lol