No. You do not have to visit a college in order to be admitted to a college. I get the impression that emphasis on campus visits is partially a generational thing. I don’t know of anyone my age (that is old enough to have kids in college) who visited the college before they showed up for orientation or the move-in day. Then again, college didn’t cost as much at the time.
Should you visit a college before applying or deciding to attend? Ideally, yes. The main reason has to do with being able to see yourself attending the college. This is more important the smaller the college. At large universities, a person can generally find a peer group while smaller colleges just may not have the numbers for everyone to find their place.
Again, this is an ideal situation and may not be as big of a deal for some students as others. You know if there is something that would absolutely turn you off (or on) attending a school. That something will depend on the person.
It’s like buying a car. There will be several that meet your minimum requirements in your price range. But without test driving you won’t know if you can adjust the seat for the best position. For most people, it’s probably not a big deal, but if you’re on the short or tall side, it’s a big deal.
The second reason to visit the campus is because some colleges view them a sign of interest and will take level of interest into consideration in admission decisions. Don’t worry if you can’t afford to visit a college, there are other ways to demonstrate interest.
And about finding out if the seat will adjust? There are ways to get that information without visiting the campus. Talking to alumni, visiting online forums, or asking the admissions office to put you in touch with current students can help you get at the same information.
Don’t forget, there’s no guarantee that visiting the campus will provide you with more or better information to use for making your decision. If you don’t take the time to do a little research before the visit, you could end up with having only the information from the equivalent of the cars salesman to show for your visit.