Last year I had to go to the US embassy in Bangkok to have pages added to my passport. For years my poor lonely passport sat on a dark cabinet shelf, wondering if it would expire with its pristine pages unmarked by stamps or visas. Then, in less than a year, it was full!
Getting pages added is free and takes less than an hour. A new passport costs $75 and takes two weeks. I'm no financial expert but it seems pretty clear which is the better deal. Basically what they do is stitch in a new passport, sans cover.
Today I had to go to the US consulate in Saigon to have pages added again! This time I can blame it on Cambodia, since most of the new pages, ten of them, in fact, have Cambodia visas on them. (I also have three Vietnam visas, and will be applying for a fourth next month). It's still pretty cool to think that in two years I have essentially filled two passports.
I was informed, however, that I can not have anymore pages added to my passport. Maybe there's a limit on the number of pages. Or maybe they just don't want me carrying around a passport that's as thick as "War and Peace". The next time I run out of pages I'll have to buy a new passport. It expires in a year anyway.