most modern machines are meant to be oiled and lubed by a tech during an annual (or at least regular) service. They synthetic lubricants used are quite long lasting and don't dry up and stay well distributed if the machine is regularly used. Having said that, I do use a drop of Tri-Flow synthetic in the bobbin race and needle bar every 6 months or so and have my 2 modern machines serviced about every 18 months to 2 years and keep them clean (which is really the most important part - keep the lint out of the moving parts and they stay moving).