You can only order one kit at a time, and you should only ever order an STI test for yourself as and when you need it, so:  After having sex with someone new (though wait at least 2 weeks) OR  Every three months  OR  Once a year, if you’re in an exclusive relationship  It's really important that we have accurate information for each person so please don't order kits for other people. Don't stock up on tests as they do expire and if they're damaged, your results might not be accurate.