The well-designed and correctly installed plumbing system is odorless. Odors are most likely to arise from leaks in the waste or vent piping, or from traps which have lost their water seal.
Frozen plumbing pipes, although inconvenient, do not constitute a calamity. The calamity may come if the pipes are thawed with a blow torch, and if the open flame or the torch is allowed to come too close to combustible material, such as insulation...
Fittings (faucets and valves) are used more often than any other part of the plumbing system. They get plenty of use but are built to take it, under normal conditions.
If your house is to be vacated during cold weather and the heating system turned off, follow this procedure carefully or contact your plumber for assistance.