Well I'd have to disagree with that. A magnet does a great job attracting most of the steel, but what about brass, and aluminum and other debri? Also although the filter does a fantastic job of filtering it begins to be less effective and more restrictive as the crud builds up on the filter surface. Lastly, transmission fluid does break down after awhile. If you want a quick check of yours, it should be clean, and light red. If it's dark and smells like it has been scorched, then it probably has, and you're well on the way to a major expense. A filter and fluid are very cheap insurance when you compare the cost of replacing a transmission at the dealership or one of the advertised transmission shops. For those that are even marginally mechanically inclined, dropping the pan and changing the fluid and filter are pretty much a no brainer. You don't need a lift and you don't need any special tools. You can do the same thing by jacking the car up and placing it on jack stands. Don't crawl underneath the car if it is only supported by a jack. Make sure you place the car in park, set the emergency brake and block or chock the rear wheels. And while you're there it'll give you a good chance to check for anything that might be loose, or leaking. Better to be proactive than reactive.