This is going to go over what I've seen regarding a saiyans potential and battle power.

DB: master roshi talking about kid goku. His potential limitless.

Dbz: It looks like the saiyans have unlimited battle power. Each time they go through battle it increases by a large degree naturally. It seems that saiyans really do hide bottomless battle power. It increases greatly the more they battle.

DBS: I'm already stronger than I was a few minutes ago. I've grown more and more powerful throughout this dance of ours.

Saiyans have unlimited and bottomless battle power that naturally increases greatly the more they battle. They can break their limits and evolve. And they get stronger through rage.