For less expensive things like every day flatware & dishes we registered for sets. China, crystal & fancy silverware was by the place setting or unit.
For things like pots and pans - I would base it on what you have and what you need. When we combined households we had tons of cookware and I really only wanted a large fry pan. It doesnt bother me that they dont match. If you want everything to match and there's a suitable set, register for that other wise choose the pieces you want.
IF it's expensive a couple of people migh chip in and get it for you. If you do pieces you might not get all of them.
