Persistent Items allows specified items from despawning from the world. You will not lose any valuable items from dying in a cave system or dungeon unless your items are stolen from hostile mobs or other players.
Also, the render distance for items lying on the ground have been extended. This helps you locate your lost items off in the distance. This option can be changed in the config file.
Administrators can control which items despawn using the new '/item' command.
/item get despawn [item id]
This command will display if the item despawn status if it is true or false.
/item set despawn [true|false] [item id]
This command will set an item's despawn status.
There are some items on the ground and administrator checks their status:
Five minutes has passed and the administrator realized that the lily pad did not despawn:
Requires Minecraft 1.6.2 or newer
Requires Minecraft Forge 184.108.40.2062 or newer