My recomendation: always have a post-marathon massage

I know that the experience of one person does not always convert to a general rule, but here's a personal experience.

I've run four marathons and after the first three I've had a 15 min or so gentle massage within 1/2 of finishing. After yesterday's marathon I had a few pressing things to attend to and did not make the time to have a massage. The result is that today I now have first hand experience of the difficulty of walking down stairs the day after a marathon that other people have mentioned. Up until now I've thought I was just lucky to be fairly free-moving on the day after, but now I don't think luck has anything to do with it.

From now on I am going to make sure I have a post-race massage.