Confused about address change -- please read and help, thanks a

I'm moving to another state soon, so just searched on this forum about "address change". The more I read, the more confused I am.

I have 3 questions:
1) Do I have to report address change every time I move as long as I live in US? or only after I ted my green card application?
2) How can I find out my address record online? I don't even know what's my address in CIS's record.
3) What will happen if I fail to report in the first 10 days? I've never realized this could cause deportation, but I hope there is a way to make up for it.

Thank you very much for your help!!