Pap every 3 years. Maybe you're thinking about the hpv cervical dna test that's done the same time as your pap smear. If your hpv test is negative, your pap smears have been normal, and you don't have new partners, then your next pap smear is due in 3 years because you don't need to be screened for cervical cancer as often. It's not a substitute though. We just have better ways to screen.
Alternative to Pap. I am am unaware of any test that is a true alternative to the pap test at this time. New tests are being explored and studied all of the time though so keep both eyes open because the only thig that is for sure is that everything changes.