Training through minor injuries vs actually resting — where's the line?

I always have something that hurts. Sore fingers, tweaked shoulder, bruised rib. It's combat sports — you're never 100%.

But I struggle with knowing when to push through and when to actually rest. Last year I trained through a "minor" shoulder issue and it became a major one that kept me out for 3 months.

Now I'm dealing with a sore elbow that's been lingering for 2 weeks. It hurts during training but goes away after. Do I rest it for a week or is this just the normal background pain of grappling?

How do you decide?