I don't advise looking at your hair from an evaluative standpoint when you need a relaxer. You should only assess your hair post touch up.
When you're extending your relaxers, you have roots, they don't match the texture of most of your hair, so the ends are bound to appear thinner...
My hair just generally looks JACKED when I'm waiting to get a touch up and I'm 10-12 weeks in. It won't style right, it won't fall right, it feels drier, and chances are I've been airdrying regularly which, if I'm not doing bona fide curls, can be a not so great look for me.
Eliza if your hair is breaking though, I'd say it's time to relax. Everyone's limit is different.