It's not really that complicated. If it's a short term engagement (3 hours literally once), then 1099. If you need them for 3 hours every week, then consider hiring them as a part time employee ... it's a long term relationship at that point. If you need 3 hours every week and engage a temp agency, then chances are you'll get a different person (even if they send the same person a few times in a row). If you engage a "temp agency" that's literally just a front for one person ... that's an employee and should be treated as such.