How many sets and reps do you do per muscle group?

Right now I aim for about 10-12 reps and I go for 18-20 sets per muscle group

im always told too much lol

but im around same 4-5 different things with 4 sets ranging from 6-12 reps
arms delts ie smaller groups do try do 3 sets so brings it down

At my age I get far more out of lower reps. Something like 5 x 5. Not the Dorian Yates intensity, but enough to know I've worked out.
I also need a lot more recovery than I did 10 years ago.