@Malik I used my waiver to cross into Buffalo this past weekend. The officer advised me to apply 6 months before expiration of the waiver. He said that you can continue using the waiver until it expires or until you receive the new one. He said if you apply too late, you could be without a waiver if the processing times increases but if it doesn’t and you apply a bit early, they won’t keep in mind that your waiver is still valid. They’d issue a new one which cancels the old one. For what we pay for it, I’d monitor the processing times here and try to apply as close to the time as possible. But who knows with some people posting that they’re waiting much longer even after having waivers before.

you can use the existing waiver until it expires