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I'm an American living in the UK with my European-national spouse, and we recently entered the Schengen zone to visit family for Christmas. As I've been living here in Europe for 7 years and travelling, mainly to see family, frequently I have quite a few entry and exit stamps, with some even having been done erroneously.
Well, the border control agent said he would normally have to send me back (to the UK) because the Schengen tourist visa requires there to be 2 blank pages in one's passport (he actually said 3, but I looked it up later on europa.eu and found it's actually 2), but that he would be lenient since it's Christmas.
There are about 10 spots for stamps left in my passport, which would be 2.5 pages if they were all together at the end, but they're not… because border control agents seem to put stamps in haphazardly with no consideration for keeping it tidy or leaving pages! Also, as mentioned above, some have wasted space by putting stamps in erroneously when they weren't actually needed.
So what are travellers supposed to do? How are we supposed to ensure that we maintain two pages free when agents ruin our passports? Are we just supposed to bend over and get new passports years before they expire, spending money unnecessarily?