I have heard recommendations that if you have any sewing machine in storage, you should take it out at least every six months and run it as it does help keep the insides from freezing up. I do the bobbin area on my Bernina's and do try and get them in for a shop service at least every two years although the recommendation is yearly. We used to have a Bernina dealer up here that included a free yearly cleaning and go over with any machine you purchased from her. I loved that service!