Channel 4 in the UK did a programme on sex education. Apparently, some German research shows that Kegel exercises alone can cure 40% of impotence in about 6 months.
We are mostly young/young-ish men here and we shouldn't have any ED, but Kegels are supposed to be good for erection hardness, premature ejaculation, impotence, etc.
If you want to do Kegels, go to the toilet and start peeing. Try to cut your urine in mid stream and feel the muscle that is working. That's the muscle you are supposed to exercise.