When deciding on the best squash bag for you, take into account the following factors:
Budget
Consider how much you have to spend and how much you are prepared to commit before you start shopping for a squash bag. As with other things, the more money you put into a squash bag, the better it will serve your purposes and the longer you will be able to use it.
Comfort carrying the squash bag
Consider the distance you'll have to carry your bag as well as the number of things you'll be bringing with you. When you have a little more items in your bag, a bag that is pleasant to carry when it is nearly empty may feel like it is cutting into your shoulder. Convenience
Think about the gear you already have before you start searching at bags (and any gear you plan to acquire in the near future). Consider how much and how often you plan to travel. Pockets, carrying straps, wet pockets, versatility, and size are all traits that most bags have.