How many is too many?
When you begin to apply to colleges hopefully you've already done your homework and researched the ones that have what you're interested in. No use applying to a big name school if they don't offer the major you want. Start with a list of about 30 that fit your requirements. You can use online sources like College Board and ACT to narrow down your choices by categories. If you have the chance to visit the ones on your list, do so. Look at your qualifications, talk to representatives, alumni, professors, sit in on classes. Use virtual tours if you can't visit. All this will narrow down your list. A good number to apply to is around 10 to 15 which include some reaches (highly selective schools), some reasonable stretches (ones that you have a really good shot at) and some sure things which could even include community colleges. That should give you a manageable number to work with and compare. Good luck with your search!