The DVDs with labels... yes, I can see those being a definite problem.
The discs without labels... they can be problematic too, but for different reasons.
Just because something worked yesterday, doesn't mean it'll work tomorrow... just ask any car owner.
The timeframe I was talking about was the time it takes the reflective coating to deteriorate on recordable DVDs. There's no established time frame for this, no charts to check, just experience.
On a well made, brand name DVD, that time frame is estimated at 25+ years. They haven't been around long enough to verify that, yet...
On the cheaply made ones, 6 mos. to 1 yr. is the usual estimate, and you've extended that slightly by saying that you've made some work by the try, try again method.
The point is, that less-expensively made DVDs (sounds better than 'cheap') have a limited lifetime, and they won't playback forever... as you are finding out.
Does this answer your question?