Question: How do you familiarize yourself with a new horse?
Answer: It depends on its age. If it’s a very young horse, chances are good that I'll work with it in hand and/or put it on the lunge line to see its mannerisms and see what it does—to get to know its personality a bit.
When I'm first riding the young ones, I'm asking them a lot of basic questions to check rideability and how they respond to lateral work and to leg. Gas pedal, brakes, and turns—those are the most important.
I usually don’t watch a video immediately because I like to get my own assessment first. If I watch videos later, then I can pick up on some of the horse's habits, to see if they are consistent from earlier. But I prefer to treat each horse like a clean slate and to make my own assessment. I don’t like to have any preconceived thoughts unless it’s something super important safety-wise, or I’m going into a class and catch riding and its trainer or rider has something pertinent to add.