When SSDs first came out their lifespan was much lower than now, and they were a lot more expensive. People wanted them to live as long as possible, so they came up with the recommendation to never place a page file on an SSD. This was sad, because an SSD is perfect for a page file since I/O is typically in small 4KB random requests.
Things have changed. The lifespan's of FLASH chips inside SSDs has improved, the wear leveling technologies in the SSD controllers has improved, and the cost of SSDs has come down. It is now safe to put your page file on an SSD. By the time it wears out, a typical HDD probably would have too, and regardless you'd likely be wanting to update that now ancient SSD. In a worst case scenario you would prematurely 'degrade' performance I suppose, as that is how SSDs start to show wear.
In my opinion, the days of worrying about your SSD lifespan are over. Sure, you could go try to intentionally kill one if you wanted, or degrade its performance, but in normal utilization, you are going to be fine, in my opinion.
UPDATE: Also see below for my recommendation to use an SSD as a ReadyBoost cache store (yes, you can do that). ReadyBoost is ideally suited for SSDs - a 'smart cache' made for that type of media. If you have any uncomfortable feeling about putting a page file on an SSD, try ReadyBoost instead.