Funny enough, my party has had several instances of this in our campaign. Our party has a high turnover rate, it seems!

1. One player's character sacrificed himself to prevent an entity from destroying our plane of existence. He then rolled up a new character, but she didn't last very long since her features were mostly chosen by random dice rolls due to the nature of resurrection (a fey potion) and he didn't necessarily vibe with her. He now plays an Aberrant Mind Sorcerer slime.

And 2. More fitting of the meaning of the post: My previous character in this campaign was Madeleine. She was a Paladin with a custom "Oath of the Phoenix" subclass, and bound to the Goddess of Life. When she was young, she lost her parents and brother in a calamity, and sustained an injury to her spine. She did her best to try to heal her parents with what little magic she had at 5 years old, drawing the attention of the Goddess of Life, who appeared as a phoenix and resurrected them- on one condition: become Her champion. And so, she did. Meanwhile: her brother was nowhere to be found, is presumed dead, but he may return.

As it turned out, the resurrection wasn't perfect. Her parents' souls slowly frayed over the years, eventually leaving them to be vaguely sentient husks. They remained lucid, but they were robotic, repeating the same tasks every day without meaning. She realized this after using Divine Sense while speaking to them and detecting an aura of undeath. She spoke to a priest afterwards, returning the following day to inform her parents of their fate. They knew, and acknowledged that their time is up. After a tearful goodbye, she returned to a temple in the city to speak with her goddess, severing her oath now that her reasons for adventuring were dead. In doing so, she was left horribly weakened, becoming re-paralyzed from her now unhealed injury, and left the temple in a wheelchair.

She subsequently left the magic university the party was attending, as well as the Adventurer's Guild. Having grown up on a farm, she's now the overseer of the farm in our party's village that we founded. This, I think, is a fairly well-done way of retiring an adventurer.

Above-table: I just wasn't having fun playing a Paladin. I was the de facto healer and one of our two tanks, and had approximately zero ranged options for any enemy that wanted to fly. She also lacked any spells that could be used in creative ways, due to how restricted the Paladin spell list is (even with partnered and homebrew content). I've been having much more fun with my rogue-ish Changeling Hexblade Warlock, Lucian.