Dear Tom and Ray:

My husband and I disagree on many things, but with this one, we both think you can help! We have a 2005 Nissan Sentra, and it's time for its scheduled 30,000-mile checkup. Because we still have the warranty, I prefer we go to the dealer and have this routine maintenance done (I hear doing it at an outside garage could cause the warranty to be voided); he thinks we'll get ripped off, and would rather take it outside the dealer network. Since we're both students and can't afford to buy a new car, we need to know what the right thing to do is! Help! -- Preethi

TOM: Gee, Preethi. We hate to be critical of dealerships. Especially since they already have "hits" out on both of us. But regularly scheduled maintenance (the 30,000-, 60,000-, 90,000-mile services) is one of those areas where they absolutely hook up the vacuum to your wallet and let it rip.

RAY: We should point out -- to that nice sniper gentleman with the rifle in the window across from our garage -- that there are plenty of things for which you absolutely SHOULD go to your dealer. Warranty work, recalls and service actions are some obvious ones. Or just good work, if you're lucky enough to have a dealership you like and trust, and that charges fair prices.

TOM: The same goes for unusual problems. An independent mechanic may see two 2005 Sentras a year. So he might not know about something that a dealer, who sees hundreds of 2005 Sentras a year, might recognize immediately. That can save you hundreds of dollars on a diagnosis.

RAY: But scheduled service is something that a lot of dealerships still charge way too much for, in our opinion.

TOM: Most 30,000-mile services involve changing the oil and filter, changing the air filter and checking a bunch of stuff. All of the required maintenance items are listed in the back of your owner's manual.

RAY: But it's not unusual, in our experience, for dealerships to add lots of unnecessary services to that list. Or simply charge a lot for checking things that can be checked very quickly and easily. We've seen 30,000-mile services that cost $400, $500 or $600 when they really should cost only $200-$300 -- at most.

TOM: Dealers may argue that there are things that should be done that aren't listed in the owner's manual. In our experience, that's unusual. They may argue that they use genuine original manufacturer's parts. But your independent mechanic can get those parts for you, too, right from the dealership.

RAY: Whatever you decide, having your scheduled maintenance done by a non-dealership mechanic will not void your warranty. As long as you can demonstrate that you have done the maintenance listed in the back of your owner's manual (your repair receipt from any repair shop, or even receipts for parts if you do the work yourself, will suffice), your warranty will remain in full force.

TOM: So, to be fair to dealers, because I'm sure there are exceptions, here's what we suggest: Take your owner's manual and go to the garage of your choice. Show the mechanic the list of required maintenance and ask for an estimate of what it will cost to have all of that work done, using Nissan parts.

RAY: Then call the dealership and ask for its price on the 30,000-mile service. If the prices are the same or similar, then why not go to the dealer? But I think you'll be shocked by the difference in price, Preethi. We have been.