I would only wear a full suit in saltwater. Too easy to get stung, brush up against a barnacle covered mooring line, or up against a boat ladder. I only dive in a full suit in any water really except a pool. If you are going to get a shorty at least get a skin to wear under it. For me a 3 mil was fine in Bonaire doing 3-4 dives a day for a week. Im Florida I want my 5 mil for diving like that. Temperature loss is cumulative and by the end of the week most people will start to get cold. It is much easier to allow a little water in to flush the suit and cool off. Rather than try to get warm when you can't add neoprene or more body fat.