I try to remember to brush out the bobbin area every change, but it is usually every two or three bobbin changes. I also take my vacuum cleaner hose and vacuum the area periodically. (I am always amazed at how much lint comes out.) I usually oil when the machine starts to get noisy. My manual cautions against over oiling. My machine has been professionally serviced twice in the 10 years I have had it. Once was at the end of the warranty period and it was free, the other time was when it needed a repair.