Any beermoney sites known for points in your account to eventually expire or wipe?

Any common beermoney sites that anyone has known for someone's account points to expire?

I put a lot of time into Swagbucks, Prolific, CrowdTap...does anyone know if points accumulated in these sites expire eventually?

Is it possible that something else may happen (maybe like a point system change or some process change) which causes user's points to wipe?