Don't need a tippet just nice to have so your not tieing a new leader all the time and to guarantee you always have a set length from your fly line to fly. I usually use either a 5 foot leader with a 4-5 foot tippet in high snag areas. And nice open areas I use a 8-9 foot leader with about 16 inches of tippet. For best casting and for me best results use a 9 foot tapered leader that tapers from 20lbs-6lbs and a 12-16 inch tippet
Happy fishing