Will my items disappear

[Jakusu]

I can’t remember if I died and rage quit but sometimes when I revisit a server I used to play a lot and had items on they will be gone. Does this happen to anyone else and how long before my items disappear again

[fall]

Items don't just disappear.
If you're playing singleplayer, unless you reset the actual map itself, items stored inside chests, inventory etc. will remain as normal. If you die, then exit, your items will be removed.
If you're on a server, a similar thing applies.
But you said revisit, this could be a while after you last played, making it a reasonable assumption that the server owner has manually reset the world, at that point all man-made structures, vehicles etc. will be removed.

[Jatapa]

Some servers have this plugin that will automaticly remove players data that has not joined the server for a while like the servers that I play its set to 7 days