1. The show has gone through major cast changes
2. Not Mash
3. Not Educational
4. Not a Sitcom
5. Not E.R.
6. One of the cast made a guest apperance on Gilmore Girls
7. Not Smallville
8. Not 7th Heaven
9. Not The O.C.
10. Not Cheers
I already said it's not a sitcom
Next Hint: Started in 1995