I'd say it has to depend on what you want to do with the straps. If you're making utility straps, that's one thing, but if you might end up using some of the straps for belt blanks, it's another story. I've been making a few heavy duty belts and cutting down stirrup straps for them. The stirrup straps don't have a uniform thickness, and hides are likely to have some variation too. If you need a specific thickness, it might be better to buy pre-cut straps. Otherwise, you not only have to cut them, you have to split them too. Of course, if you can get a pretty uniform thickness hide, the whole argument goes out the window.