At Wetwear we recommend A back zipper, they are warmer and easier to get in and out of by yourself. Our back zippers are on a slight angle from the center of the back neck to the left hip. This makes zipping easier both on and off. The only time we would not recommend a back zipper is if the person is claustrophobic or dose not like things touching or tight around the neck area. Being that all of our suits are made to order, we can put the zipper anywhere you like. As for needing to relieve yourself, we can do the double slider front zipper or if the zipper is in the back we can put a 6" relief zipper in the front. Hope this helps!