It depends on what you sell. If you sell primarily clothing - you should list a return policy since you'll have to accept returns whether you like it or not.
I have never offered returns in my listings, but I also don't list items as "rare or mint or like new". I sell primarily collectibles and books - the clothing items I sell are mostly t-shirts, jerseys, and hats where "fit" is not an issue.
Now just because I list "no returns" does not mean I don't accept returns if a buyer is unhappy with their purchase or I made a mistake in the listing. The few returns I've had were items that I relisted and sold a second time.
For most items I would rather accept a return than issue a partial refund to keep the buyer happy.
