Seeing as I live in the Bay Area, we don't have dust, we don't have electrical storms, no moisture, no nothing. If an earthquake hits, the cover isn't going to help. Mine sits in the sewing room in it's table 24/7. The only time it gets put away is when I take it to get serviced, every couple of years. Of course, it's not one of them 3 to 10 thousand dollar Rolls Royces you all sew on, just a 1970 Bernina 830 Volvo. 10 years now I have been sewing on it and never had an issue with dust or power fluctuation. Of course I don't even cover my woodworking machines, just dust them off after use. Living in this very boring weather center has its advantages.
tim in san jose