Having a pit's nice (have one in one of my grandfather's garages) but the spiders that gather there don't half take lumps out of you (my father seems to attract them for some reason). And keep an eye out for mice, there's been more than one occasion when I've had my car in there over night (once to replace the engine in a 205 diesel and two head gasket replacements for my coupe) and when I've turn on the heater there's a puff of peanut shells coming out of the vents (my grandfather has a tendency to feed the birds, and more recently badgers, peanuts).