Why are they wearing cheerleader costume?

One thing I always find weird is that in TV show Glee the girls in the cheer leaders club are always wearing cheer costume, even when they are doing other things, or even at home. I saw that in Heros, the girl with a superpower also was wearing a cheer costume outside the school.
Is this the usual thing that happens in the real world? I personally find it weird, wearing such a short skirt (and silly costume) in the street.
Sorry for such a silly question, but my head is full of question marks whenever I see such scenes (well the Glee started their new season...so.)

It's just for TV because people like to see girls in cheerleader costumes. Normally people only wear the cheerleader costume at cheerleading activities. Sometimes there are periods (especially at the start of the season or when the school's team has just qualified for a championship match) where uniforms are worn all through the day for a while, but that's not the normal case.

However, it -is- somewhat normal to wear skirts just as short as cheerleader skirts in the warmer months, especially for single women in urban environment (ahem... when out for the evening. Not at work, not at professional events, and definitely not at church. So not 'normal' clothing exactly, just not unusual going-out-on-the-town clothing.) Such short skirts are not so normal perhaps (even for summery night-life outings) for high school girls in small towns like Glee is supposed to portray, but for women in their twenties in other parts of the country, they are not entirely unusual.

Thank you for your clarification. I'm glad to know that everything is normal in the real world.

As for the short skirts, here in Japan as well it is quite commonly seen. Especially in Japan, many of the school girls make their school uniform (pleated checkered skirts, especially) very short almost to the minimum limit. Btw school uniforms are sort of a formal wear for those students, so naturally you can go to funeral or even to church with this mini-skirts

I can now watch Glee in peace.. thanks

I've seen girls in McDonald's in their Cheerleader outfits once or twice. I assume they get changed when they get home - although I'd like to think they sat around all night like that.