Other than that, I can't really figure out the purpose for credentials. I've kept some of my good ones for twenty-five years. Maybe, I think that one day the market on eBay for a 1974 Boston Marathon press pass will pay for my kid's education. An Albuquerque Journal photographer told me that one day he will build a house with a bar. The bar will have his lifetime of credentials pressed under glass, and when he drinks and tells war stories and lies, he'll have the souvenirs right there, to jog his memory.
Some events spawn a great credentials grab.
Perhaps the greatest was the O.J. Simpson trial. Because it went on for so long, and because it caused so many creative people to stay in one place without anything to do, O.J. passes, permits, and heirloom quality IDs were created for everyone. The toughest credential I applied for was News Media ID issued by the Los Angeles Police Department. They take enough information for a major background check, a full set of fingerprints, a letter from your freelance employer, and your baby teeth, if your mother saved them. I'm keeping a baby tooth from each of my children, just in case the LAPD will need them one day.