This depends upon the type and usage of the machine, however, we recommend having your machine professionally serviced every 3 years. Many modern machines keep a tally on the number of stitches you’ve done and will warn you if it thinks it needs a service. Some old machines have the ability for you to oil the mechanism yourself but you should still have the machine properly cleaned, oiled and adjusted regularly to get the best out of it. Be aware, also, that some manufacturers warranties require the machine to be serviced at specific intervals in order to maintain the warranty, so you should always check your user manual for manufacturers recommendations on maintenance and servicing.