It depends on what you paid for the DVD player. If it's a low-end unit, think of it as a toaster. You pug it in and either it works or it doesn't. When it breaks it's not worth more than perfunctory troublehsooting before you buy a new one.
If you have a high-end audiophyle unit, you may (should) be willing to do more to protect your investment. One thing you can do is clean the lens. Find yourself a non-abrasive cleaner that won't damage the lens. Although there many abrasive cleaning products sold, they should never be used on a lens. Cleaning the lens should be done at least every 100 to 200 hours of play or every month. If there are smokers in the house, the lens must be cleaned more frequently.
Good luck.
