|Here's another tip that is probably obvious to most people, but sometimes the obvious escapes me! Lubricate your machine on a regular basis, according to the manufacturer's instructions.
I am quite good about cleaning and oiling my sewing machine on a regular basis, and I dust or vacuum out my serger after every project. But today, I took a break from the home-dec-job-from-he** to make DH a new bathrobe. It's a KS pattern that is easy to serge. So I ran it through the serger, which started making all sorts of unpleasant noises. I heard a joke recently, "When you're a kid, you hear something go bump in the night and you think, 'What's that? Is it coming to get me???' When you are a grownup, you hear something go bump in the night and you think, 'Oh great, how much is that going to cost me?!'" Well, that's what I was thinking.
BUT, there turned out to be a much simpler, cheaper solution. I put a couple of drops of oil on the joints, and suddenly the machine sounded a thousand percent better. The moral of the story is, lubricate your machine regularly. I hate to admit it, but I don't think I had oiled my serger in about 10 months, and I use it non-stop. I find that oiling my machines after 8 hours of use (which I do on my sewing machine), keeps them humming along without hiccups. Same with most sergers (even if I have not been following my own advice).
The caveat here is that you should check your machine manual to be sure. There are some machines (my old Viking is one) that don't need or recommend oiling, just regular service. As I say, it may sound obvious to some, but it is helpful to remind myself of these basic rules every so often!