To answer the original question, when I was younger (late teens ho phase), I hooked up for sex alone, usually with friends or acquaintances. I always used condoms and to this day have no STDs, not even HPV, which is endemic. The only thing that stopped me was I fell in love and he was everything I wanted. Now that I am older and we're no longer together, I wouldn't go back to random hooking up because, other than disease, as much as I hate to admit it, I now like to be romanced and stuff.
Perhaps I am paranoid; but I ask for proof of their last HIV test status. If they have never had one done we hold off on sex and I go with them for the test. You probably think I'm being a prude but I think I am being safe.
Unless you are holding off for three+ months, with STD tests at day 1 and day 90+, and complete celibacy in between, this guarantees little. But, it is good that you are taking a stand on testing. I think far too many people feel they "know" someone after a time or bang them for awhile and then trust they are disease free rather than test.
For me, even in LTRs I use condoms (yes, even for oral early on, but not hand jobs.) and require testing - there have been issues with this in my relationships where some thought I wasn't trusting - but maintaining good, disease free health supersedes everything else.
Also want to add, many communities in the U.S. offer free STD testing. Most vary in what types are free, however, HIV tests are generally always free. Keep in mind, they are usually swab tests without backup testing... I spent years volunteering at an HIV wellness NPO and am kinda a snob about testing. There is no reason not to test and when you get the results back it's like "Ooooooooh, I passed!".