It does only take one time to get an STD, STI or HIV. Of course the chances are less than if you have multiple partners, but if you sleep with someone without knowing whether they are infected then once is all it takes.
If you have no symptoms or outward signs of infection, then Better2Know would suggest the full STD screen. If you have blemish, spot, lump or blister then we would suggest that you have a Blemish Screen which will take a swab of the area you are concerned about and test for Herpes, HPV and Syphilis.
If you are female and have unusual discharge or odour then we would suggest a Comfort Screen.
Everyone’s circumstances are different, and it is your responsibility to choose the tests that are right for you depending on your sexual activity and what you know about your partner. If you are unsure then Better2Know recommends a Full STD screen. Once is enough to catch an STD, STI or HIV.