Can't answer any wetsuit questions, I dive dry.
But most shops rent computers. Computers due "learn" your profile and adjust. But most rentals don't get enough dives from say one person to really affect the profile. Truthfully most people who dive alot own their own, so the profile is usally for shallow dives which then should make to computer a bit more conservative for deeper dives. Or if you would feel better, they may be able to clear the memory so it acts like it is brand new and is more conservative.
Even though I have a computer, I still plan my dive, look at my tables just so I know in the back of my mind the times I am allowed. The computer just credits you for time it takes to get to the max depht and back up. If you do a dive and make a max depht of say 60 feet. Your average depth might only be 40. Your dive table is going to say you can only stay down 60 min. But you computer is going to go "we were only at 60 feet for 7 min" then calculate how long you can stay at 40 or what ever extending your bottom time.
But most shops rent computers. Computers due "learn" your profile and adjust. But most rentals don't get enough dives from say one person to really affect the profile. Truthfully most people who dive alot own their own, so the profile is usally for shallow dives which then should make to computer a bit more conservative for deeper dives. Or if you would feel better, they may be able to clear the memory so it acts like it is brand new and is more conservative.
Even though I have a computer, I still plan my dive, look at my tables just so I know in the back of my mind the times I am allowed. The computer just credits you for time it takes to get to the max depht and back up. If you do a dive and make a max depht of say 60 feet. Your average depth might only be 40. Your dive table is going to say you can only stay down 60 min. But you computer is going to go "we were only at 60 feet for 7 min" then calculate how long you can stay at 40 or what ever extending your bottom time.