We are planning to visit Buckingham Palace, as well as watching the change of the guard. Reason why I am not booking the visit to Buckingham until right before the month when we are supposed to go there. Why? Because some months have the change of guard every day, while other months have it only every other day.
I don't want to book my ticket for the day they are not doing the change of the guard, and then have to go back to the same place twice.
When I plan my trips - live and learn - I plan them in clusters - as much as possible of course - in order to avoid wasteful zigging and zagging around town.
Here is a website that can give you info on the change of the guard.
Changing the Guard - Ceremonial Events - The Household Division - Official site