5mm sound warm and nice, but then I guess it will be too warm at 30C (86F). The thing is that I only want to buy two suits, three is a bit too much if you ask me. I will probably do a lot of diving in 20C (68F) and below, so the dry suite will come in handy. I'm not sure if I will mainly dive in temperatures around 23-25C (73.4-77F) or 26-30C (78.8-86F). 3mm will probably be fine for 26-30C, but I feel a bit unsure about 23-25C. To be honest I don't really know what the temperatures are around the world, nor do I really know where I will be diving. Guess I can always rent a wet suite but that's not half as fun as owning one. Unsure if I should try to find a wet suite for waters around 23-25C or 26-30C. *scratching his head*