It is very similar to what the Pest Control Industry does for Shops and Food Establishment's .
It has Four visit's in a Year and if you have a problem in between visit's there is no cost to the person who has the Plan.
I had a bit of a problem though about a Month ago when someone wasn't real happy as I didn't turn exactly Three Months after the Service was started . The times are not scheduled for exactly Three Months .My Computer warns me that a service is due but we are dealing with Nature and a service may be a Week or Two early or Late . It may be raining when the Pest Sprays are due or another time may be better for a Rat Rebait for example.
No Biggy , but I must not have explained it correctly . As always Call if you have any problems .