My 15 year old grandson, now a tall chap with a deep voice, still had Teddy sitting with him until very recently, whenever he was using the computer. (Teddy, very worn and now quite limp, has been with him since birth, and I knitted him a cricket sweater and scarf last year to give him a bit of street cred.) In the past few months, Teddy stays in the bedroom now, as Chris has discovered GIRLS..... and his girlfriend is only allowed downstairs.
When we were on holiday a few years ago, in Helsinki, I was buying a small moose wearing a knitted sweater with the Finnish flag embroidered on it, to join my collection of soft toy moose and reindeer (which my husband thinks is a bit sad!), and a man, travelling with his family asked if he could take a photo of his Teddy (yes, really!!!) with my new moose.... Apparently this teddy travels all over the world with the family, and has an appropriate photo at each port of call! So, the moral is: you're never too old to have a Teddy bear. My elder daughter still has hers on her bedside table, as she has had him since birth, but my younger daughter was never particularly bothered about hers.