My 950 Adv came with them installed and they've obviously taken some abuse. Personally I mostly slab it so I probably don't "Need" them. However they make a great resting spot for my legs if I need to stretch out a bit on longer rides, allow me to mount up a set of small bags I got from a member here that conveniently carry my wet weather gear and jacket liner w/o the need to have bulky panniers, and they allow me to give my bike some much needed orange.
1998 KLR-650 (wrecked)
2000 KTM 950 Adventure (sold and regret it)
2001 KTM 640 Enduro/SuperMoto (sold, no regrets)
2008 Honda Shadow 750 Spirit
2011 Kawasaki Vulcan 1700 Vaquero