Do colleges care about volunteer hours?
They care about what you did and whether you stayed, not the total. Why there is no hour threshold, and what makes service read as genuine.
The short answer
They care about service, not about the number. There is no hour threshold to clear for admission — what gets read is what you actually did, how long you stayed, and whether it connects to anything else about you. A hundred hours at one organisation over three years says considerably more than four hundred hours spread across eight one-off events. Some scholarships and some graduation requirements do set specific totals, and those are separate from admissions.
Where hour totals genuinely do matter
Three places, and it is worth separating them from admissions. Many high schools set a service requirement for graduation with a specific number attached. Many scholarships — local ones especially — require a documented total. And service organisations and honour societies frequently have their own minimums.
All three are real reasons to keep an accurate record. None of them is a college admissions threshold, because that does not exist.
What makes service read as real
Staying. An organisation you have been with since tenth grade demonstrates something a day of volunteering cannot, regardless of the hours attached to either.
Doing something specific. "Volunteered at a food bank" is weaker than "ran the Saturday intake shift and rebuilt how donations were logged", and the second one is usually available to anyone who stayed long enough to notice a problem.
Coherence with the rest of the picture. Service that connects to what you study, or to where you live, or to something you have said elsewhere in the application, reads as a person. Service chosen because it seemed like the sort of thing that helps reads as exactly that.
The version to avoid
Hour-collecting — attending unrelated one-off events to accumulate a total — is the least valuable use of the time, and it is visible. A list of single-day activities with no through-line is a recognisable shape.
If the choice is between forty hours somewhere you will return to and two hundred spread across a year of unrelated events, the forty is worth more, both on the page and to the organisation.