I know that many people expect that just because a player skips while playing movies, that it's a sign that it's old, but there are a couple of technical reasons for that:
1. Layer-skipping: I'm not sure this is the technical term, but there almost always a slight pause (skip) when it is time to go from one layer in the movie, to the next... (higher-end DVD players will not be as sensitive, therefore not as noticeable)
1. "E-prong" updates. Like computers, DVD players have decoding software and memory that it needs to decode the data and play it. During my retail years selling mid-high end equipment, we always knew by our repair facility that e-prong updates were needed every 1.5-2 years to update the built-in software and kinda reset the cache-RAM-equivalent memory from errors that it accumulated and where not deleted, therefore running out of memory at times of processing the data and creating a skip.
I'm sorry this is totally UN-TECHNICAL (especially for any AT forum), but it was explained to me about 2 years back in this same manner and I bought it. And now I'm too tired to research the real terms and technicalities, so if anyone knows more specifics, please feel free to explain.
Xolus