I have heard from a restaurant owner that the week between Christmas and New Years is the single busiest week for restaurants on SXM, so other than for very casual places, you probably should make restaurant reservations for dinner, yes. We have only been fortunate to be there Christmas week once and calling once we were on island, we were only able to eat at one place at 6 PM one night, even though we gave the owner a whole week to pick from. This was one of the premier restaurants on the island, but that week was packed at all the best restaurants. For lunch, you MIGHT need a reservation at someplace like Bikini or one of the other big ones on Orient, or at Anse Marcel Beach Club, for sure, but not otherwise. Otherwise, wouldn't think you'd need reservations for anything.. Enjoy!