They all have "shoot" in common.
They all have warmup strokes, though some insist on doing these strokes in sets (like do 3, if you're comfortable yet, do exactly 3 more, repeat as needed)... possibly some advise to do the same number all the time no matter what.
They don't all have the pause in the backswing, though I personally think it works great.
I don't think it's super important to my game. People have made the point that maybe after 10 years of doing the same stuff, I have developed a routine without even knowing it, and it's somehow helping me. Maybe that's valid.
Nevertheless I never made a conscious effort to do anything the same way every time except stroke the ball. I don't chalk the same way (or even on every shot... terrible I know). I don't fret about my foot positioning. I don't worry about my breathing. I don't pay attention to my practice strokes. The only thing I work to do the same way every time is stroke the ball.
So my routine is basically:
1. analyze the table. Don't get down on the shot until 100% committed to a shot with a specific dime-sized leave area.
2. Get into my shooting stance, any way that feels natural.
3. Take warm up strokes while I'm dialing in my angle and speed
4. Shoot when I'm ready, never before (often with a pause in the backswing)
If you're looking for some general opinions on how important routines are, there are some longer debate threads already out there. I've seen good posts from preshot fans and the 'just step up and hit 'em' guys.