I'm a frequent needle changer, too. I put in a new one for every project and if it's a larger quilt I change again before I start the quilting. I figure it's cheap enough to do that without damaging my budget and ... it can't hurt! I started this when I was having FMQ troubles- one of the variables I was trying to adjust. I hope I've worked those out, but I still change frequently.

chaning machine needles
 

I change my needle whenever someone on here starts a thread like this, Thank You.

I think changing needles for each project matters. I recently meched a Singer 500 and, with the needle that was in it when it came to me, it skipped stitches, had an uneven tension, and the stitches just didn't look as good as I thought. It sounded clunky. I installed a new size 90 needle and all those problems cleared right up.

I change needles with each project or every 8 hours of sewing. My machine works best with a good needle. I also oil each time I start a new project - and clean every couple of hours.

I change needles when I hear that "clunking" sound, that actually means your needle point is dull and is having to "punch" through the fabric. Some of my needles last for 2-4 quilts, others barely make it through one. I just wait till I hear it punching through the fabric and change.

I clean the bobbin area when I change my bobbins. It gets very messy!

I can only remember to change mine when I hear the "popping" sound as I sew as it punches through the fabric! I don't really notice any difference other than that sound, though. I figure on some small level it works the machine harder to have a dull needle so maybe by changing the needle promptly we get a little more longevity out of our darlings(??)

When I first started quilting, I did not sew every day, or even every week. It was a once in a while thing. The needle lasted a long time. That was my old Singer. My new Brother (3 yrs old in July) I like to take better care and change it when it starts to seem to be straining.

I only change my needle when I detect a problem with the current one. Sometimes this can be quite frequent (if I've stitched over too many pins or if I've pulled it out of alignment somehow) and other times it may be several months.

I bought my needles in bulk - there are 100 in the box - with a coupon sale at my LQS. That way the cost per needle was so low I change my needles with each new quilt.