|Short answer: there is no way of knowing.|
Flash drives do have a limited number of writes but for normal use this should not be a problem. The quality and reliability of flash drives varies widely. Unfortunately you can't often tell who the manufacturer is from the brand name. Many brand name companies simply buy from whoever has the best price at the time.
At the present time flash drives are the least reliable of modern storage media. You must always have another copy of important data.