I rarely use straight knitting needles, although for many many years I did not even know that they had circular needles. I've been knitting for over 60 years and the knitting world as everything has "come a long way baby".
I now use interchangeable circular needles for almost all of my projects. The weight of the project distributes better on the cables therefore taking the weight and strain off the wrist. And when you knit as much as I do you want to save your body parts as much as you can.
I also carry these knitting projects from place to place and the tips need protection some times so the stitches don't fall off the needles. Here is my solution. It originally held beads but I kept the container it just looked too handy for holding things. I simply used a razor blade and cut a small slit at the bottom. Voila a Circular Needle Protector with a crochet hook in case you drop a stitch.