What kind of message do you get when you repair it? After you repair, you are saying it goes away for a while, then comes back?
Assuming you are not powering down while booted or something that would cause disk corruption, this sounds like a drive headed for a dirt nap.
🙁
You might also try running the
Apple Hardware Test and see if that turns up anything. It is possible a bad memory module could lead to disk corruption, although this is less likely than a bad drive.