I’ve never seen it live but always try and watch if I can. Back when DS was in junior school and DH working at the MOD in a “shop window” appointment, he was given four tickets by his boss for seats in one of the stands. DD was very small then and I knew she wouldn’t last through it, so we stayed at home and DH took DS and a friend from school. They had a wonderful time and talked about it for ages afterwards.
The drill has changed a lot over the years, but is never less than impressive, especially the wheel movement that the massed bands do, for which there are no instructions -it’s just sort of “handed down” and, apparently, if you are a young bandsman in the middle of it, it can be very scary indeed!