The first cloth is still in use after 4 weeks. Its been in the washer too.
Wash well to reuse. No idea how long they'll last but still going strong a month on and washed weekly.
I'm getting really excited about the options to replace plastic (and put one in the eye to the plastic and petrochemical industries), and so these are an effective addition to my guilt-free arsenal! I'll never use those plastic wrapped blue things again.