The cost of insurance will depend on when your renewal date is.

Make sure there is nothing is writing incl text or email suggesting anything other that the lease is NOT being renewed no matter what he does.

If they don't leave you will have to evict them.They are M2M, so, just give the actual tenants a 30-day non-renewal.

One month is  rather typical, and if they renew, they typically get a bonus for the renewal.Gino

If the lease is ending be sure you have given the proper notice of non-renewal of the lease.

For me, managing lease renewals is not a big deal.

I've been a Pro member for several years, but am coming up on renewal and have changed direction to Notes. 

Your post says she gets a month of rent if the tenant renews.

One other manages one and agreed to 8% as well of just the rents and when a new tenant comes in, I pay a new lease up fee (but not for just renewals yrly).

If it's a student property, we're prepping them with renewal rates by January 1, and they have to renew by February 1 (for a lease that starts in August).Do not ever rent by the bedroom.You're not a matchmaker and don't want to be their parent when things go south.