Thats exactly why we didnt renew ahead of time, he had an Esta in place that covered him and realised that if we got a new passport (we had even got so far as filling in the passport application online and it had been posted to us for signature) would then have to renew the esta (in December) and knew we weren't going to be needing it taill at least the next July so would have lost 7 months of the 2 years validity of the Esta. You can renew your passport anytime but only up to 9 months unused validity will be added on. Luckily wont have that problem for at leat another 8 years as we have both renewed passports now.
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