For non-clinical community service, people often aim for somewhere around 100 to 150+ hours total. Service specifically directed at underserved communities tends to carry the most weight with admissions committees.
Once again, consistency is what actually gets noticed, not the raw total. Volunteering at the same soup kitchen every Saturday for two years says considerably more about who you are than a single one-week service trip, even if the trip's total hours look larger on paper. Pick something you'd genuinely keep doing even if it never appeared on an application.