Some I have been in contact with for over 10 years and get regular updates - sometimes just a christmas card with an updated picture or notes on what the kids are up to. Those that move away tend to stay in touch with me more than those that move on within the city. Think there is something about holding on to a piece of your past so it is there when the kids are old enough to appreciate it that is important. I have done a lot of care for military families so moving on is just a part of our lives. The ones that stay in contact are the ones that left when their children started school so were with me for 3-4 years as in I was the only caregiver that child had. The ones that leave when the kids are younger for whatever reason are less likely to stay in contact after.