fitting travelling boots

Put them on, make sure the legs are protected all the way around (ie no gaps where they fasten or at the top), check the horse is capable of walking, then pull and twist in every direction to see if they move. There may be a more scientific approach, but I find that if you try to move them in everyway they could possibly be moving, and they don't shift, or shift very little, they're good.
 
newrider.com