Ricardo had a post at his blog discussing some symptoms that signal whether you've been travelling too much.
- You know your passport number by memory.
- You know the date your visa to a certain country was issued.
- You know the crew of your international airline of choice by name, or at least recognize their faces.
- You have seen most of the Academy Award nominees in the comfort of your plane seat.
- You feel more comfortable having dinner at Dallas Fort Worth international than at your local downtown area.
- Most of your books have been purchased at an Airport book store.
- But the worst is when you start to recognize Customs and Border protection agents! This happened to me on my last trip."
To which I added:
But I guess my dad is the ultimate authority, as his passport shows what happens when you've travelled too much: