“I have seen may kids graduate in 5 or 6 years”
I think that the majority take at least 5 years, although many students graduate in 4. One reason for taking longer is a late change in majors. Another is if a student has a bad semester or two and needs to drop classes or repeat classes with poor grades. For some very demanding majors some students do better if they take 4 classes at a time instead of 5.
We tried to make sure that we would not have a disaster if things went 5 years, with no aid for the 5th year. Fortunately our oldest did graduate in 4 years and our youngest is solidly on track to do the same.