These shirts actually fit really well out of the box. Unlike some other more loose fitting shirts I've gotten from Proozy, these didn't need any tailoring which was great. But here's my tip: If you're going to wear them as just everyday casual wear, or very light activity, I think they're fine as is. However, if you're going to work out in them like I do, doing any kind of repetitive motions that use arms and shoulders (arms, chest, back, shoulders workouts etc) then you're probably better off cutting the sleeves off (like I did), then they're perfect for workouts. With the sleeves in tact, your mobility is somewhat restricted due to the more form fitting nature of the shirts. So just know that before buying, but it only took me 3 minutes to cut the sleeves off (just turn the shirt inside out and cut right along the seam). Otherwise a near-perfect shirt as it wicks away sweat and doesn't heat up under heavy workouts.