Our daughter still likes one of us to stay with her till she is asleep. She is 5 and husband and me don't mind. We quite like the quiet time at the end of the day with her and to give her that reassurance. She did go to sleep on her own for a while when she was 2/3 after gradual retreat, and she sleeps ok when babysitter leaves her or grandparents. So she can do it, but after a bad experience with (other) grandparents, we've sort of gone back.
She also woke up much more in the night when we left her to go to sleep on her own, so we'd rather do this than having bad nights.
Has anyone who's done the same found that it affected their children in the long run, and did the child decide at a certain age they just didn't want you there any more?