I use circular needles unless I am making socks. I make hats and use a 16" circular for those, but I like dpns for socks, which I dont use very often. When I use dpns, I make sure to move a few stitches to an adjacent needle making for a bit of a rotation so that there is no obvious (though slight) vertical gauge change line where I changed needles. I hope that makes sense. Not necessary to do that if you tighten up a little as you change needles, working your way around the tube, but thats kind of annoying to have to do.
I gave up using DPN’s. All knitting even in the round can be done using Circular needles. It’s my sole preference now. I keep my straights and DPN’s in a nice vase as show...
I like to use circular needles until the diameter is too small and then switch to dpns ETA I loathe magic loop; Id much prefer to use dpns but I do have some very small fixed circular needles.
I hardly ever use flats as its so much easier to keep my stitches on circs and more crowd friendly.