Between 5-7 unless there are special circumstances. The number of colleges you apply to depends on the competitiveness of the college, the need for financial aid the desire to participate in collegeiate athletics. We suggest 1-2 reach schools, 2-4 target schools and 1-2 backup schools that you would be willing to attend.
This is a good choice if this is the school you want no matter what. Check with the college to see if it is binding. If so you must attend if you are admitted. Many college have other options such as early action, a better choice, This is not binding.