For how many years requip (ropinirole) is an effective treatment for parkinson's as the decease progresses?

That Depends : Requip (ropinirole) is not a cure nor will it lessen the progression (or I'm unaware of such evidence)....however it's benefit on symptoms of a movement disorder may be present as long as you take the medication, possibly many years. If you think it may no longer be effective, then discuss with provider. Maybe a dosage adjustment or maybe a trial off/on the medication is reasonable.

Variable: Treatment effectiveness with Requip (ropinirole) is variable and unpredictable depending on each patient/case.