If weather is cold an rainy? If weather is super hot? Same warmup every time?
If anaerobic threshold is 170, still 5 minutes on 190?
Stretching 10 minutes? Sometimes stretching legs means group or person opens gas fully open
Stretching muscles 10 minutes, if done like long static movements make muscles super soft, lazy, non-responsive? It must be done lightly after warmup ride and less than 10-15 sec/movement for main muscles and riding position spesific muscles. Like that it works.
Good for my age? Teenager? If young kid, then warmup in some cases can be shorter because heartrate on teenager is still quite quick responser and muscles are small, this way more ability to 'jump start' Too much on a warm day and you preload your body w/ heat = disaster.