How Long Should I Use The Spears Karma And Fierce Thunder For? (any Recommendations)?

I'm currently a level 52 Warrior, in Olux Swamp. I've noticed that Karma has higher average spell damage (and better spell spam capabilities) than its counterpart, Fierce Thunder, has. I'm using both aforementioned spears because Fierce Thunder can hit mobs that are weak to it very hard. However, these are level 39 spears, and I'm in my 50s atm. Should I consider swapping out these spears in favor of spears around my level? What spears should I go for?

My build is a Water-Air build, with some emphasis on Defense and Dexterity (crappy build, I know, but I wanted life steal and spell spam to be part of my Warrior [War Scream+Life Steal=Lots of HP]).

Thanks!

 

Just keep them til level 55, you get a good spear from a quest.