If a lease is up, do you have to still give a 30 day notice, if you are not renewing the lease?

Yes, you have to let the LL know what your plans are so they can either advertise the unit or not. Your ex cannot put you on the lease without your signature. A lease is a contract that must be signed by all parties. But I would send the LL a letter stating that you will not be a signatory to any lease renewal effective [expiration date of current lease]. It would help the LL to know what apartment or living unit you are a signatory to.

the landlord would be remiss if he didn't have you sign a new lease when the first one expired unless he automatically puts you on a month to month rental, then the one who remains in the rental and pays the rent would be the one to notify 30 days in advance of vacating the premises

your lease has expired, it is no longer valid

Yes you do.

Yes you still need to give 30 days notice to leave

yes

Yes, you have to inform the landlord 30 days ahead of time as the lease automatically goes to a month to month. Good landlords check with you but it is your responsibility to tell them ahead of time if you are leaving

It is still considered courtesy so the landlord can put the place up for rent.

what did the lease say?

to be safe, you should notify management company more than 30 days in advance that you have moved out and that you will not be extending the rental term nor signing any new lease even though your ex- may choose to do so.

No, the lease is up, unless you do plan on renewing you just leave

However, your ex may not qualify to renew the lease without you being on it, and in that case he would be asked to vacate the place on the day the lease expires