I used to record shows... or try to.
You have to, without question, use the cable company's box. No other box will work. Let's put aside the question of cost, and further, let's assume that it costs me $0 for cable service including the box.
The DVR that my provider game me would start and stop at a few minutes before or after a show. It couldn't be predicted, but about 10% of the time I'd miss the start or the end of the show.
Sometimes I wouldn't get any sound on the recording. That was about once a week. It's tricky at best to watch a show without sound.
Other times the recording would be pixelated. Sometimes it was for a second, sometimes it was for a few minutes. Not really a deal-killer.
About once every couple of months the DVR would erase every recording I'd ever made. So if I hadn't had a chance to watch a show, I could never watch it.
It was pretty bad and the cable company gave me a $100 a month credit for a year to compensate me for their crappy system. Now let's get rid of that cost assumption -- it wasn't $0, it is close to $100 a month to get a box that doesn't record and an encrypted feed that gives up. I'd guess that about 25%-35% of the time the show was unwatchably corrupted or just gone. (There were no problems watching a show "live", just when recording.)
Which meant I had to rent the shows... ooh, wait, there's no rental place that has them.
Okay, I can buy the DVD... oh, it won't be out for a year and I'd have to buy the whole season for $150...
Does the library have a copy to loan me? No.
There is one alternative...
I've never had a problem when renting from the famous Swedish library. Never once have I had a bad video, missing audio, or anything else. What you have is a free system that provides error-free and convenient watching of shows. The other option is expensive, error-ridden, and a pain in the ass.