1 - THE FIT
After all, it's not a cheap purchase. Off-the-rack suits use a “standard sizing,” which is one-size-fits-all approach to suiting that uses only chest size and jacket length to determine your “ideal” fit.
Important factors like:
Sleeve and trouser circumferences
In addition to the above, what about your posture, and the shape of your shoulders? The list goes on. Your body is a unique shape and size so even if you think off-the-rack sizing is ok for you, there will always be one area of fit that's not quite right.
Getting the perfect suit fit is a game of inches… well 1/4 inches actually! A good quality men's suit is one that's made to your exact body measurements. PERFECT