Not all hotels in Madrid have user friendly phones in rooms. At the Hotel Suecia, which is an otherwise excellent hotel, they did not have telephone card accessible phones, so I had to go to the lobby and talk to my family next to the reception desk, which was awkard, when I was telling sweet nothings to my Hubby

Renting a phone is a personal decision. I wish I had rented a cell phone. I did regret it, particularly for Madrid.I didn't do it because I did not want to stand out like a guiri. But when I was there I noticed everyone had a movíl. The convenience of making a call at any time balances the high cost of rental, at least for me. I wasted a lot of time looking for phones and then finding I had the wrong card, etc.

Calibasco is right that they are expensive to rent compared to the calling cards which were very economical, and all the other inconveniences, Calibasco is ALWAYS Right .