Without a good set of well fitting hip pads you may find any advancement in your paddling skills impossible. Basically if your seat is wide enough to slide a hand between your hips and the seat walls, you’ll probably need to add hip pads to customise your boat’s fit.
Hip pads help you tilt and lean your kayak when you’re right side up, and help you stay inboard and roll when you’re upside down. Provided you don’t make the shims too tight, your boat will comfortably grab your hips and your level of control will skyrocket without your leg going to sleep minutes after entering the boat. Remember that when you pad up your seat that you will be wearing your paddling kit when you use them on the water. Will you still fit; will they be too tight or not tight enough?
Many of the new outfitting systems allow you to add shims quickly to the standard set up. This works really well and allows you to adjust your outfitting throughout the year. During the winter when I am wearing my drysuit plus a few layers of kit I need less shims than in the summer when I might be wearing a pair of board shorts.
If you suffer from numb or dead legs after sitting in your boat for a little time moving your pads a little up and back usually cures it.
Stretching/increasing a paddler’s flexibility also helps.
California Kayaker Magazine had an article on some other options related to outfitting to solve numb legs in their Winter 2010 Issue (#4), which can be read online for free at calpaddlermag.com/magazine.html.