The law of perceived usability

If it looks usable, then you probably still can use it. As long as you don't check if it should work, and as long as it isn't a printer.

One of the new things those who survived the Extinction had to adapt to was how much some of the things have changed once the material and spiritual worlds have merged. One of the things that take some time to get used to is the appearance of the things affecting their usability.

The buildings

The buildings are affected by this new property. In the houses that are clean and look nice, it will be warmer, the electricity can be used and one will probably find freshwater. On the other hand, no matter how good are the pipes and cables, they will be either impossible to use in the house that looks neglected, or their quality will be drastically worse. The lights will blink and flicker, the water will be dirty or will have an awful taste or the rain and wind will go through the holes that aren't even there.

The items

Even the smaller items, such as weapons, electrical devices, and vehicles can be used despite their true internal condition as long as they look good on the outside. As such, it is possible to artificially make things work or be better at what they do than normal. This property has been used in a few interesting ways such as: making a blade of a weapon look shiny so it cuts better, not checking firearms for bullets so they can still be shot as long as the number of shots doesn't exceed their possible capacity, or fixing cars with some duct tape, cardboard, and airbrush.
Some people even started making usable devices by carving their replicas in various materials. As long as they look convincing enough, they can be used.

The power

As long as the power source isn't checked, the things that should operate on power and look like they could, will operate.

The food

This rule is also why there haven't really been any food shortages since The Extinction. About 50% of the places that should have food inside them will have some fresh food in their storage once they are entered, no matter how long has it passed since it was possible for them to be produced. Said food is normal, material, and safe to eat without any negative consequences, though Spirits that live in the area will also know that said place is a great location to hunt.