get as many hours in as you care about, there's obviously "metrics" that you should try to hit but if you just try to achieve a set arbitrary number to please an adcom they will see right through it. love service? give back to underserved people you can in your community as much as possible. want to show your dedication to medicine and get practice in the field? work a clinical job part time or full time. some schools will req a set amt of shadowing 50-100 hrs but anything more than that is overkill.
also, getting the bare minimum benchmark of hours in an already very competitive ecosystem of applicants is not the way to go- do everything in your power to remember your why and do activities that reinforce that. after "Applicant X" writes all over their app that they love to help the underserved and their mission in medicine is to give back to health disps but they have only done 250 cumulative volunteering hours in the community, maybe they shouldn't apply to service heavy schools w/o more experience
yes, med school could use stats to filter people but unfortunately no one other than school-specific adcoms would know. do your best to make your app the best it can be and dont rush it.
