Termites: Spot Treatment or Whole House Termite Treatment?

One of my buyers is buying a house that has pretty extensive termite damage. The seller has reduced the price so my buyer can have the house treated for termites and repair the damage after close of escrow. 

My buyer wondered whether she could just spot treat the areas where the inspector found termite damage. Some damage is visible from the attic access, and it's not possible to see the whole attic because heat ducts block the way. It's safe to assume that more damage will be detected when the heat ducts are removed.

I told her she can not do a spot treatment instead of the whole house treatment. The termites will just go around the treated area. 

After the whole house is treated for termites by a licensed termite contract, it will have a one year warranty. If termites reappear within a year of the treatment, the company that did the treatment will spot treat. 

Because the termite infestation is so extensive, I told her to have the house inspected again six months after treatment, and definitely before the one year warranty expires. Inspections that do not involve the sale of a house do not need a report filed with the state, so the inspector will usually do the inspection for free. 

Some termite companies will do a cursory inspection when the house is under warranty, because they don't want to find termites that they will have to treat. I told my buyer she should not try to save a few dollars on treatment. She should just have it done by a company that I think will be thorough and do a serious inspection, even if it means they have to do some treatment under warranty.

If termites reappear within a year of a whole house treatment, it doesn't mean the treatment was done incorrectly. It just means that the termites have found a way into the house by a route that wasn't treated. In a house with room additions, there are several gaps in the slab where termites can get in. The termite company will keep focusing on the newly infested areas until they eliminate all the termites.

If the termites were attracted by a leaking faucet, roof, irrigation line, or rainwater that ponds next to the house, the termite problem will probably persist until the conditions conducive to termite infestation are remedied.

After the whole house is treated for termites, the termite damage must be repaired so that if/when new damage appears, it will be clear that it actually is new damage. When damage is found in the attic or a shed of one of my houses, I paint over any repaired areas, write the date of the treatment on the repair, and keep the treatment records. The State of Arizona only keeps termite treatment records for five years, so they are usually not helpful in documenting treatment.