Wiring mistakes can kill or burn down a house months or years after they have been done. You will not notice unconnected protective earth or badly dimensioned circuit breakers until something else breaks and the protective element is not there.

There are many failure cases that are slow. Especially with water. Let say they sag a bit and connection is poor. It might slowly start leaking over months causing structural damage or at least dampness and microbiological effects.

I'm in the midst of renovating a house at the moment, it's about ten years old.

The plumber siliconed all the shower valves to the fiberglass walls without screwing them to a backplate.

Unsurprisingly the builder is now out of business.