Pull ups I shoot for 50 total. First set 30, 1-2min rest another 10-15 followed by 10.
Lately between pushing them to the end of my workout at the tail end of a very long day (I usually hit the gym 8:30 -10Pm) at the end of a long week. I've been squeezing out 20\10\10\5\5.
Also, the amount of time I spend on pulls up depends on the quality of ass the girls on the tread mill are carrying since the pull up station is ideally placed for viewing.
Chin ups (close grip) I can do 30\20\10\10 but generally don't bother.
For reference, I'm 5'9 188-195lbs