Many of my bad habits were changed because I bought a new (and expensive) sewing machine. My worst habit, by far, though seems to be talking to myself. Not a problem at home, but when I used to go to quilter's night out or classes, it generated whispers amongst the quilters.
Otherwise rotary blade - I don't change it until there is an annoying nick.
Pins in mouth - yes
Needle - sew until it breaks
Pressing after every seam - yeah, right.
I stopped sewing over pins, as a habit, just a few years ago. I so rarely use pins and it was costly enough to bring my machine in for a broken needle stuck under the race.