Every method book has Opinions about warm-ups, and I suspect nobody actually does what they claim. So, honestly: what do the first ten minutes at your instrument look like?
Mine, truthfully: one slow scale if I’m being good, then straight to the piece I’m excited about, then guilt.
Honest version: open strings, long bows, 3 minutes — non-negotiable, my teacher can hear it in everything else if I skip it. Then one three-octave scale in the key of whatever I’m working on. Then the hard spot from yesterday before the fun run-through. The order is the whole trick.
Chromatic thing for the left hand for two minutes mostly to stop my brain checking my phone. Then I comp through a tune I know cold. Warm-up for the hands is overrated for guitar IMO, warm-up for attention is everything.
From the teaching side: the guilt is more harmful than the skipped scale. A warm-up has one job — to make the next twenty minutes better. For some students that’s five minutes of rotation exercises, for others it’s playing literally anything they love at half tempo. Prescribing one ritual for everyone is how we make adults feel like failures over scales.