This is really so personal and dependent on the objective of your ride that day (clinic? lesson? riding at home?) and the horse you’re on – as well as the horse you get that day.
I will say the best warm up for my current horse when we are not at home is to hack him around the venue/place at the walk for 15-20m before I get into the ring. We don’t need to do much warm up at other gaits at all, in fact I prefer not to, to keep my horse fresh as sometimes these clinics stretch for nearly two hours.
At home I always do three loops of my bridlepath before entering the ring, which adds up to about 14m of walking.
I have never warmed up for 45-60 minutes before jumping a horse. At most, my warmups – especially for XC schooling or clinics – have been 20m of walking and 10-15m of W/T/C over fences. If I did 45-60 minutes of warm up I would probably be on my horse’s back for 2 hours once everything was factored in.
I see the value in working on lateral work and adjustability in these warmups, but the focus should be on improving these at home so they are ready tools for your disposal at clinics.
Some food for thought is if you are trucking in, your horse is already ‘warmed’ up in the physiological sense - balancing in a trailer is hard physical exercise. I find the longer the ride is, the more the horse needs a walk warm up to get those muscles used to balance to relax. I think I would have a tired horse if I rode as hard as some of the advice in that panel.
But, I also am not riding an UL athlete - so my horse’s fitness is nowhere near as hardcore, and my goals are not that high.