if you stay close to shore
you wont need a roll right at first, since its hard to roll in very shallow water anyway. You can practice leaning and bracing in 1-2 foot waves in 2-3 feet of water. As soon as you start venturing out into deeper water and bigger breaking waves, you'll want one. Its important to remember to tuck when you capsize in shallow water-not only for protection but also so you can get out of the kayak. If you happen to be leaning backward when you capsize in shallow water, you will have to lean forward anyway in order to free your legs (unless your kayak is very poorly fitted). Getting into the tuck underwater can be more difficult in very shallow water because the bottom interferes, so its best to make sure you capsize in a forward tuck in shallow water. You can still get into the forward tuck if you must but it can cause some unsettling feelings if you have to try, so its best to avoid it. ;-) You'll definitely want to have your wet exits well practiced before doing this sort of thing.