My panel is outside (common in Southern California). In theory my FPE 100A panel was good for 80A and my total non EV load was 13A. The breaker tripped on a 40A Toyota EV charging. Breakers are mostly thermal and when the sun heated it up the working breaker did not pass go.
Anaheim required a 200A panel when replacing so I got rid of the evil FPE panel and I have much more breaker space. I will never come close to pushing the panel but it is always good to have a reserve.