Or, can I just have them sign the new contract which would have a rent increase and pet deposit/fee? 

Twice as much body dander is being produced and going through the furnace filter.

On our application any pets have to be approved and that there is a extra monthly fee.

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

Don't listen to anyone here unless they are practicing real estate law.BP is fabulous but the biggest pet peeve I have with BP is that everyone is a self proclaimed expert.

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

I was kicking around pet rent but my wife is super opposed to it. 

While I am familiar with the ADA response to this topic -essentially all favorable to a tenant, but it appears there is an abuse of the definition as they are all employed, functional individuals who leave the assistive pet at home all day.

They are your pets , you and your wife alone should be held responsible for any damages they cause .