The problem: Old food in the refrigerator gets mold.
It happens that some food gets hidden behind newer things and only when the refrigerator gets quite empty by accident these things appear again.
The reason: It is easier and faster to put new things in front of the things that are already there.
When coming home in the evening with a lot of bags full of content to be stored in the refrigerator you probably want to quickly put everything away. Everything is stuffed in the refrigerator quickly to get you bags empty and move on to the next action. Along with this older food slightly shift to the back. Getting older the family members focus on the newer things before needing to examine the older food in detail if still good. And so older things get older and finally begin to mold. Then either a long time can pass until found and thrown away.
The solution: Always fill your refrigerator using a system.
I do organize the refrigerator in the way that I can use the items in the same way as reading a book: I use items from top down and from left to right. So I put new items on the right or below. Where possible I leave a little space to fill newer items behind older ones (especially for yoghurt). Exceptions are only vegetables that usually go down into the vegetable drawer.