Every 3 months is quite the standard recommendation for sex workers. Every 3 weeks/1 month is ridiculous, and a heavy burden on the public health care services. It's not "free" at these sex clinics, it is coming out of tax dollars. Chlamydia, and to a lesser extent Gonorrhea is easily treatable with a single dose of dual therapy antibiotics. So don't get your panties in a bunch, everyone should be regularly testing every 3 months. If you are punting and undergoing risky behavior, you should be testing every 3 months as well, it's not just the WLs. You should all be upholding the same standards as them to keep your risks down. Not everyone experiences symptoms with many STIs, that's why you should be regularly screening every 3 months.