I'd say they do wear normal clothes day to day. We've seen pictures of them dressed casually too. They do dress them in a very old fashioned way for these types of occasions. Charlotte doesn't stand out so much and now that George has progressed to suits, he doesn't look out of place either but the shorts and knee high socks combo for Louis is very Victorian looking.To be fair, they do tend to dress them in very old fashioned and restrictive clothing. Hopefully they wear nicer stuff day to day