You're in mile 18 and all you have to do is get to the next water station. Up ahead you see them. The group of happy cheering volunteers handing out half-filled paper cups of water. Only a few more steps and aawwhh! You're there! Take a break! Walk a few minutes! And enjoy the sights and sounds. You deserve it!
Thought I'd add in a short note about marathons. They say you can't begin to think about your next one until you've forgotten your last one. Initially, it was easy for me to sign up for my next one. I ran my first 26.2 miles in December 2008. It was the Las Vegas Marathon. I ran it with two knee braces and took 5:47 to finish. But before the end of the year, I was already signed up for the Country Music Marathon in April 2009. That was not an easy race by any means - 96 degrees! Being a glutton for punishment, I was signed up for the Denver Marathon in October 2009 by May. I guess I brought the heat to that race too - 85 degrees! And to increase the pain even more, I crammed another race 7 weeks later. I returned to Las Vegas for the inaugural Rock 'n Roll Marathon. No knee braces this time around and the new course, low temps and overall great experience paid off - 5:32 new PR!
Four months later and I'm not signed up for anything! Actually the only race I've ran is a 5K. I don't know what's holding me back, but I'm eye-balling trying again in October - without the heat this time!