Any time you have a moving part, small pieces of metal come off of it. That is what lubrication is for. If you have never oiled your machine, you still are damaging the parts and they will fail eventually. The type of lubricant you use is important because many change viscosity as they heat up and some just plain get "gummy" over time. I can't tell you how many times I've heard the "I can't believe someone ruined this because someone didn't do..." in an industrial setting.
Many of us call our machines our "baby" and unlike our children these actually come with instructions. I don't read my whole manual but I always read the troubleshooting and maintenance section. When something doesn't make sense (or work), call the dealer and ask. Your baby will thank you (so will your checking account when you don't have to take a machine in for maintenace).
My husband reminded me this morning that my serger wasn't "humming" quite as nicely as hit should (it is all mechanical not electronic so it is louder than some) and was time to take it to the garage (I use the air compressor to blow out the lint and stuff before I lubricate). Got to love a guy who "listens" to the sound of machines.