E-mail response question?

[mcfanfordreamy]

I have been writing a lot of letters via e-mail and I was wondering if you do get a response back from (Example a athlete) and they promise they will try to get a autograph to you:

1. Respond to there e-mail thanking them?
2. Length of time you should wait and should you ask them again if it's been a while?

I am wondering what is the proper procedure in these events. I don't want to seem ungrateful in anyway or disrespectful in anyway. I know with athletes especially that they are busy training and I feel kind of weird bothering them but I do love giving my support and I have gotten a lot of responses, so I am a little curious on procedure. Thanks..I would love any advice you guys have. {thumb2}