I read an interesting analysis on the lifespan of some of the Google service and API that has been cancelled: http://www.theguardian.com/technology/2013/mar/22/google-keep-services-closed
Based on the analysis at the time of the writing, Google service has a mean lifespan of 1,459 days.
An interesting point to ponder, especially if your applications/services depends on one or more Google services.
Screenshot below:
