The signs to watch for
The same ones that led to the first treatment: the surface looks dry and chalky, granules are washing into the gutters, and water sits in shallow areas after rain instead of running off.
Those signs show up before anything fails, which is the right moment to act rather than after a leak starts.
The term is a guidepost, not a timer
Every term in the range ends eventually, and the length depends on the treatment and the band the roof scored. A roof that was treated in a higher band has longer before the surface needs attention again.
Re-treating early is not harmful and re-treating late is not a breach of anything: the score is what decides, and it is measured when the question comes up.
What the price lock is worth
A future re-treatment is priced with a 20 percent lock under the warranty, so the work is not starting from a fresh price years later. It is one of the few things in this category that rewards planning ahead.
Ask for the clause to be pointed out in your estimate so you know exactly what it covers.
What happens at the second visit
The same thing as the first: the roof is scored, and the band on that day sets the treatment and the term. A roof that has aged into a lower band is treated for that band rather than for the one it was in before.
If the roof has moved to the Replace band, you will hear that, and the conversation becomes a replacement plan rather than another treatment.
Why the roof is measured again
A re-treatment is quoted against the roof as it is on that day, not against the paperwork from the first visit. Years of sun, water and freeze-thaw have moved the score, and the band it lands in now decides what can be issued.
It is the same discipline that applies the first time: no quotation without a measurement, and no term that the condition does not support.