Here is the checklist that I walk through in my head when shopping for suits:
Where You’ll Be Swimming: Swimming in the ocean and lakes affect the suit less than swimming in a pool with chlorine.
How Often You’ll Be Swimming: Like any piece of clothing, the more you use it, the more it will show the wear, but if this also includes a chlorinated pool, the rate that you’ll see wear will be much faster.
Price Point: By answering the first two, you can figure out your price point for the suit. Typically, the better quality suit, the higher price point.
Repurchasing: Think about how often you want to repurchase your suit. Is this a yearly occassion? Every other year? Every few years?
Rotation: The number of suits you have in constant rotation will definitely help with the wear and tear of your bathing suits.