Your wetsuit should fit comfortably enough to enable you to swim unimpeded. A wetsuit that is too tight will quickly result in shoulder fatigue. A wetsuit that is to loose will take in too much water. It must be pretty snug when you put it on, however, not uncomfortably so. If it chokes you or you can’t easily raise your arms then it is too small. Remember too that once you enter the water the wetsuit will loosen a bit. Scoop a little bit of water in through the neck area and make you final adjustments. Work the suit up snugly into the crotch area and push the sleeves up a little further to release pressure on the shoulder area.