No "non-compete" contracts?

Do all firms require you to sign a non-compete clause when being sponsored for your series 7/66?

If no, who are they?

If yes, Are there any companies that provide a contract requiring less than 2 years of employment before they can work for another time firm?

Are there any other better alternatives?

I'm determined to get my licenses but don't want to limit myself for who I can work for in case of unforeseen circumstances. I want to be able to use my licenses with another employer and continue my career without being sued. Please help me figure this out.

Thanks Guys.

-F