One year later, and I still come across mouse shit. It got everywhere. Under every seat cushion, every dresser drawer, on top of the fridge, the tv, the computer desk, every cupboard, on top of cieling tiles in the basement. EVERYWHERE. Any soft hearted feelings or no-kill solutions to rodents has been tossed out the window in my book. No execution method for mice is too cruel any more. Fast and effective is all that counts.
Spiders are fine. Like a few others here I leave them be in out of the way places so they kill other bugs (kinda surprised to see others do this, thought only a lazy INTP like myself would consider this approach).