|I know this is terribly obvious, but being a skinflint, I haven't replaced my pins in years and years! I finally got fed up because, even though I religiously throw away pins that are bent, really dull, or sticky, I was still having problems pinning a pattern onto some fine knit.
I got some new IBC silk pins and, boy, what a difference! I guess pins get dull gradually (like everything else), so you don't really notice until you try to pin something challenging. So now I'm going to try to remember to replace my pins every couple of years.
The other thing I found out is that new pins are really, really sharp, and if you don't want to have little drips of blood all over your fabric, you need to place them on your magnetic pincushion so that the tips aren't pointing up! It takes about 5 minutes to arrange them on the pincushion with the heads pointing out, and saves a lot of pain. It's easier if you do this *before* you dump them on the magnet, so that they don't get magnetized and stick to each other.