On the Pioneer DVR-107 or R07 inside the Sharp DV-RW250, the lens degraded after recording many DVD-RW’s over the years.
But that also made CD-RW’s undetectable “No disc” (until trimmed laser potentiometer). CDDA playback has actually improved because of Better disc readability at lower potentiometer (laser trimmer) settings and higher speeds?
DVD-R also got unreadable (detection process faulty), DVD-RW surprisingly only when the drive heated up. Then, the playback also ceased.
DVD-Video DL also was just occasionally readable. And if it was, only after 10 to 20 hiccups.
DVD-Video SL was readable only after many hiccups and struggles during the detection process. After that, there were no hiccups at all.