Yesterday was the first day I turned on my sewing machine in 2009. Before spending any dedicated amounts of time with my needle going up and down, I took a moment to thoroughly clean out my machine. Gave her new sips of oil and a fresh needle too.
This is my favorite sewing machine cleaning tutorial. It does help that she has a Bernina like I do, and we share a lot of common components. But even if you have a totally different machine, it's worth taking a few minutes to pop off the faceplate, open up the bobbin area and use a q-tip to swipe at any lint you can find.
One of the best things I have done for my sewing machine is to buy bulk amounts of needles. If some thing is the slightest bit iffy on my machine, one of the first things I'll do is swap out for a new needle. I don't try to delude myself into thinking that it's still kinda sharp... I can sew some more with it. You never know if the needle is bent, misshapen or weak. It's not worth fussing over your tension or thread breaking for one single needle.
Currently, I'm a member of a Yahoo! Group call Needlecoop. Once or twice a year they do a needle order. (They are required to have a minimum of $1,000 order from the group before they can make the purchase.) I can buy 100 Organ needles for $9.00 and $4.50 for S&H. They have an order set up right now, due to close January 31, 2009. I've put myself down for another 100 needles (which I've been using to both piece and free-motion), and 100 needles for my mom, as she was almost out when I was visiting at Christmas.
I hope you've taken a few minutes to get lint and gunk out of your own machine. :)