You said they are good tenants, give them the chance just moniter the inspections regularly.
Kids from my experience with a tenant did more damage to my property than their animals (which I allowed, as had my own, and had to rent elsewhere at the time with my own dog) trusting the RE agent (now know better), as I was living far away at the time.
You may keep them for years if they can fulfill a family thing of having a pet.
JMHO
CG
