With the result being effectively that almost all provisions you looted yesterday are rotten the next day. The exception being salami, which last a few more days, but eating too much of it makes you take damage after going to the bathroom. You also get a stacking debuff.
The only way to not have to eat the salami will be to log in within 8 hours of picking up some veggies or something. 8 hour rot timer.
Further, the only canned food in the game will be decorative unlootable assets. You will notice this and it will annoy you. Especially because there will be a campfire asset used repeatedly in both the world as decoration and in rest stops as an interactable. (As a general crafting station that includes an option to cook meat to reset the 8 hour rot timer, but also has the options to make and repair clothes, etc. Having it be just a cooking station would be too visually appropriate.)
That campfire asset will always have the same opened half eaten can of beans in the same place with ridiculously detailed modeling of the sheared metal rim, and an equally detailed model of a can opener lying in the dirt next to it. It will seen like an intentional prank. It will be an internal community joke. It will later become clear it was a bought pre-made asset and the developers will seem to not understand why it's funny when the topic is brought up, and will try to use the opportunity to explain the merits of their food system. It will be a confusing, frustrating, and stressful time for the community.
the rot timer is calculated based on when the item is picked up using real world time. if you reload a previous save then most likely all of your things are now rotten
That, honestly, kept me from enjoying Fallout 3 after being introduced to the series via FO4. I understand that far in the future everything is going to be shitty and broken, but the raiders that just jumped me didn't seem to have any problem getting hits with their useless broken pipe weapons that I can somehow use to repair 5% of the durability of my shitty pipe weapon.
Fallout 3 is a shit game (The classic example of why is that things like stealing a spoon will get you sentenced to death by mob violence) Play Fallout New Vegas, it's built on Fallout 3's engine but instead of being designed and written by indentured interns at Bethesda it was made by people who are, you know, game designers. (I would kill for a NV-esque sequel to F04)
I'm currently making my way through FO3 and I haven't even discovered half of all the POI and I've been playing for months. NV piques my interest, because the story telling in FO3 is great, weapon durability aside.
Give NV a try. I don't think there's any reason to make sure to finish FO3 first (spoiler-wise), and you might end up liking it more.
They're both decent, but pretty long, so playing both back to back would be way too much Bethesda-jank for most people (though NV is def better, it is the same engine).
If I had to choose one, it would be NV every time.
Ooh! And if you have anything less than 100% durable then the game has a little flashing icon warning you it's not 100%. Couple that with the repair cost being the same regardless of the percentage missing!