On the "Model Engineer" website there is a warning regarding the potential for damage to machinery due to the increase in the numbers of spikes on mains electricity supplies in cold weather.
http://www.model-engineer.co.uk/ (on the home page)
Oddly enough we recently had a microwave oven fail, and its replacement failed a few days later - in both cases a distinct "phutt" sound plus the smell of hot insulation (as John Rudd would say

).
Given the cost of repairing or replacing the controller boards of lathes and mills perhaps it is worth playing safe and using surge protection. I already have.