I have a Juki TL98Q - I clean inside around the bobbin after every project. I also take the cover plate off the feed dogs and clean that out after each project. An amazing amount of lint builds up in that area very quickly. I also use qtips to clean behind the tension area, and any other place I can get to with a qtip. I take better care of my sewing machine than any other appliance I own. It is probably the most expensive appliance that I own!