I call myself a Senior Research Fellow, but in the end I'm just a postdoc in the late 40s who has almost no chances to get full tenure and has messed up his life for good.
Before anyone blames me, think twice. I've got new contracts offered with almost no effort on my behalf over the years, and all my positions where pure research with no teaching duties. It's not easy to turn down such seemingly generous offers and try to make a living in another way (with a background in linguistics & philosophy!), even when you know these contracts won't last and only delay the inevitable.