3 ms·Just try them, there's a 14 day no-questions-asked return policy.by askafriend 4y agoJust try them, there's a 14 day no-questions-asked return policy.rozenmd 4y agoThey start breaking down after months, not days.pivo 4y agoMine have been working fine for a year and a half, haven't noticed any degradation. Not saying that doesn't happen, just that it's not a given.