The idea of a list of things to do has been around as long as humanity has had lists. In the latter 20th century, folks began building lists of things they wanted to do before they died, activities to add meaning to the dash between the years of their birth and dead chiseled on their tombstones. I have no idea who called such lists "bucket lists." I do know that I don't have one and neither does my husband.
I find the idea amusing, but have had far too many instances of life kicking me in the teeth to write something like that down, much less schedule those activities. The furthest I go is to say, "We plan to travel when my husband retires" and "We want to visit Italy and Ireland." Anything more specific and more scheduled waits until we get very close to that date and I'm ready to book the airline tickets and inform clients that I'll be out of the office.
Bucket lists make for entertaining fodder when it comes to developing stories. I've read several romances in which the heroine (usually) dedicates herself to a love one's bucket list after that loved one dies. She either meet the hero in checking off the items on the list or he helps her fulfill that commitment. Or maybe a bit of both.
I'm not sure why it's always the heroine who gets sucked into working on someone else's bucket list, but that's how it goes down in the books I've read that feature such a trope. You'll probably never see such a plot catalyst in my stories.
So, no bucket list for me. I look forward to the day when I can act upon whimsy and no longer feel obligated to plan my spontaneity.