What do 3 years of residency actually look like?

Hi all, I am currently applying to medical schools and am still a bit confused on the specifics of residency. I am mostly interested in primary care medicine. I know I can expect to work 80+ hour weeks for 3 years, but is this non-stop? Like is it 80+ hour weeks for 3 straight years, or is it 80+ hour weeks for the duration of a rotation, with breaks (small or large) in between? Does it get gradually easier with each passing year? Thank you in advance!