If i am sexually active, but safe, how often should i get tested for stds?

Early and Often: You should get tested (and your partner) before having sex with any new partner. Its also a good idea to get testing every 6-12 months with a doctors visit and exam as well. You may need more frequent care if you (or a partner) are more risky - ie unprotected sex, multiple partners, anal sex, IV drug use, etc...

Not usually: If you are truly safe and have no physical or functional symptoms, there should be no reason for you to need an std evaluation at any particular interval. Knowing your partner, limiting your number of partners, regular self exams and listening to your body, should be your guidelines.