My first machine, I had for over 30 years. I maintained it myself, cleaned it regularly and kept it covered when not in use.
I now have 3 Janome machines (MC 10000, 6600P & a 5024) as well as an overlocker which is almost 30 years old.
I used to have my machines serviced every year but my machine mechanic has told me I only need to have them serviced every two years as I keep them so clean. He has said on more than one occasion that my machines are the cleanest he has ever seen.