When I moved into my apartment the manager, a friend of my rooomate, had me sign some documents to add me to the lease. My roommate has been at residence for over 15 years. I signed the documents when I moved in 7 years ago. A few years later all residences of the complex without leases were given 30 days to vacate. I was not asked to leave. The complex has changed ownership at least 4 times during the 7 years and I have never been asked to leave because I didn't have a lease.

Recently my rooomate has given my a 30 day notice to vacate... I have told her in writing that I will not. That I have a lease...

(Yes I understand... I should leave if there is any anomosity but, I can trust her to be fair and lawful... if not a friend and I cannot afford to move)

Can I use the defense that I have an implied lease since I had signed lease documents and was not asked to leave any or each of the three times they managment/owners got rid of people (roomate etc) without leases. Also, all rent, letters etc coming in both of our names?

IN court you will of course have to provide copies of the documents you signed.

Also unless your lease automatically renewed, you would have years ago went to month to month.

Also even if you have a lease, at the end of the annual term of the lease you can still be asked to leave. So if you had a yearly lease, and signed it in August, then each August you can have them end your lease and give you notice to leave.
** Varies in some areas where price control and rent controls are in force from city laws.

In most cases, everyone can be asked to leave, those with leases just at the end of the lease.