My old laptop got 70-105C randomly. And it still worked fine. 100C is when fan went faster. 50C is just fine.
Basically you should be worried after 75C imo.
What CPU do you have? How hot does it run on maximum load (use Prime95 to find out)?
I had 70c when idling, after dusting I got a good 50c.
75c on full load now. 30c on idle, cleaned it a bit
I never hit 10)% usage