Do you have to use Proactiv your whole life or can you stop using it once acne has cleared up?

I want to know because I've had acne on my face for 4-5 years now. Really bad when I first got it 5 years ago, but for the most part it's pretty tame now; only get breakouts once in a while, and usually in the same spots. For the most part I only have blemishes now (red patches that don't rise, embedded in the skin). I was wondering if I took Proactiv and my face clears up, will I have to take it for the rest of my life? Or can I stop once my acne clears and just use a gentle exfoliating cleanser and some type of astringent? Also, I heard that if you suddenly stop Proactiv during the regimen your face breaks out really bad and all over, is that true?