I learned here about Superior Threads. They have several YouTube videos about thread & needles.
http://www.youtube.com/results?searc...thread+therapy
I haven't tried the titanium oxide-dipped topstitch needle they recommend yet, as I have a small box full of needles to use up, first. Standard needles we change every 8 hours, or project if we don't want to track needle time. their recommended needle costs $1 more per pack, but lasts 10 times longer. You change it when you hear a change when the needle hits the fabric, goes from a hum to a thunk. (all this gleaned from the above linked videos, I'm no expert by any means.)