Generally accepted size of envelopes?

[ParadiseNinja]

Hey all, i'm totally new to this, but there are quite a few people I would like to sent requests too.
I was wondering, do I send a self addressed A5 envelope inside my original A5 envelope?

Is A5 generally the most accepted size?

Thank you.

[kimmylee]

You can use any envelope size, it's down to personal choice.

And yes, most people fold another envelope of the same size in half as their sase inside the envelope to the celeb.

[Gomez1234]

I put an 8 x 10 inside of a 9 x 13 because I don't like the idea of folding the return envelope. But that's just me.