Don't ask questions. Just get it.
Seriously, it's just a better way to watch TV. If there's a show that you like to watch you set your DVR once and it will record the entire season for you. You can of course set things to tape once as well. If you get a dual tuner, you can tape two things at once. You can also watch recorded tv while recording live tv.
I always start watching my shows 15-20 minutes after they start and just fast forward through all the commercials. Also, I can forward through all the "junk" that I don't like. For kids shows, its's great because they can watch their shows whenever they want. Same for me to. I don't have to worry about the kids interrupting me. I can just wait until after they go to bed.