second the note on singapore reducing the password validity length to 5 years.

they are also lowering the fee to be commensurate to the new lower validity date.

Multiple personalities. ;)

No, seriously, I carry a second passport for business purposes. I frequently need to submit my primary passport for visas. If I need to travel in the intervening period, I can travel on my second passport.

Here's more info: Second Passports

Mexico issues passports for 1 year, 5 years and 10 years. Your choosing. The more years, the more expensive too, but the less expensive on a per year basis.