Four similar problems in the past two years? That's a really significant failure rate. Once in two years could possibly be just a one-time glitch but is still something that's notable, four times indicates there's some problem you shouldn't ignore.
It isn't likely, but possibly the card slot in either your phone or your PC is faulty and causing premature errors when writing to this microSD card. Do you have any other cards and are they also having a this problem? If not, this sounds more to be a matter where the card is able to still work but only marginally. Ideally if you do things like always dismount the card before removing it you shouldn't have any problems with it but four separate issues isn't typical at all. It might be better to just replace this card with a good, reliable new one, they're relatively inexpensive and its your data you should take into consideration.
