Where's the line with a casual encounter?

I'm personally the kind of fellow who would not commit without giving sex a try first. I'm sure this is fairly common, the try-before-you buy mentality.

I'm confused by where that mentality falls between seeking casual flings versus seeking committed relationships. If you try before you commit and then don't commit, did you just breach the boundaries of someone who doesn't want hookups? Does this merely have to do with intent?

Additionally, if you do hookup with someone who just wants hookups, but then keep trying to hookup, are you contradicting that initial intent?

Please help clarify!