I'm not a great golfer and have days of muffing, slicing, hooking, topping, and other golf evils as do most other persons who don't play that often. However, sometimes the shots actually work and the ball goes as visualized. I've found golf to be highly influenced by mental attitude and confidence is the secret to many of those decent shots. With Titleist ProV-1 balls, somehow I have considerably more confidence that the ball will behave than with other brands. This has been true for Titleist balls for me for 22 years or so, and whether or not there is any technical reason why this is true (even if it's because they're expensive), it works this way for me. Whenever I try new snazzy brands, less expensive brands, or used balls picked up off of the fairway, things seem to go sour in a hurry. Therefore my opinion is that one would be crazy to save a few dollars on a lesser golf ball and risk not enjoying your day on the greens. The case of 4 sleeves sold through Amazon are identical to new balls sold in pro shops.