Recorded media of any kind can potentially cause additional wear on your drive components because it has a lower reflectivity then pressed media. This doesn't necessarily mean it damages your laser, it just means it has to work harder. Over time, all laser devices wear down--it's just a law of physics issue. As it gets weaker, it will begin to fail to read recorded media. You will reach this point sooner on cheaper media because the drive strains harder to read it, and will fail as the components reach a certain decay level. Changing to higher quality media at that point will work as a temporary fix, giving you time to replace the unit--it won't be long until it fails with pressed media at this point.
Rips can cause alot more wear because it is a conversion from a different media type. DVD streams data at 1350KB/sec, so it has to stream the equivalent of 9X on a CD, which is near the limit of a PS2's CD transfer rate So, by design a rip will push the drive to it's limits--it's not exactly rocket science guys. So long as you stick to quality media and avoid extended play of rips (or avoid them all together), you should not experience any noticeable drop in performance under normal circumstances. Granted, there are exceptions. There are some versions that have had problems with weak lasers to begin with, some with poor drive mechanics that have trouble with tracking rips and Princo DVD-R's, etc.--but in general high quality dupes (not rips) and a properly installed modchip combination will last for YEARS to come. I've been playing my v5 quite hard for almost 2 years now on almost entirely dupes--I think I've kept maybe 6 original DVD and CD games--and my box will still read DVD-RW almost as well as a pressed DVD, just a bit slower on the load times.