I'm extremely messy and leave stuff everywhere and have food wrappings of various stuff all over my desk etc. But I never ever let trout lie around long enough for it to start smelling bad. Either my stuff is dry and therefore doesn't mould/rot/whatever, or I dispose of it before things go bad.

I seriously can not understand how people can live with the smell of old spoiled food.

I do clean things up before people come to visit me, though. I care too much about what other people think of me to let things just lie around.