Is there a concrete sealer that shines > 4 months?

So I've got an exposed aggregate driveway and walk. Have used a few different brands of aggregate sealer, and it will have that deep wet appearance looking like a million bucks for a few months then it starts to go away and eventually it looks unsealed again. Last product was bought at a concrete supply store on the advice of a contractor, but same story. Is that just the way it is?