When they can't be read anymore but in a couple of drives, skip an freeze in about any standalone player, there's no need to even think about drive deterioration.
You also seem to miss that most of the people who have reported Ritek G05 degradation have several drives, and use other discs as well, and didn't notice problems with them, only with the Riteks. So you can rule out a drive reading issue.
BTW yes, thanks to the rate at which some of these G05 degrade (not all do that, but I'd avoid the crapshoot), there has been several comparisons between original scans vs. consecutive ones, showing a dramatic increase in errors, sometimes in periods as short as two or three weeks. I can show you some before/after scans if you like, I kept a couple. They're pretty scary.
Now I'd like to add that everybody on this board seem to think that all Ritek media is unstable, though the degradation problem has been consistenly reported only for G04 and G05 produced after mid-2004. Degradation problem with +R Ritek media, or older G04, has been very scarse. So it's not a clear cut.
Two interesting threads:
And here is an extract of a post of mine in another forum in 2005:
"Ritek is totally ruining its reputation with all these quality control problems with G05 production, ending in so many different grades available. Same happened last year (2004) with G04 discs.
Furthermore, it induces senseless and endless arguing between DVD enthousiasts, because some RitekG05 (or G04) users have used the good stuff and are convinced that those who used the bad stuff are delusional (user error, burner incompatibility, whatever) and same thing the other way round, those who used the bad stuff are convinced that those who used the good stuff only try to defend the media they use or are mindless newbies."