I reconfirm all my reservations and have central reservations email written confirmation. I print out a reservation when I'm satisfied and bring the electronic copy/confirmation to all hotels we stay at, in case there are detail discrepancies.

My reservations can get complicated combining different packages, rates and promotions. Added are suite upgrades, point upgrades, status, etc. I've ran into many discrepancies over the years, in fact 1 every 5 or 6 reservations will have details missing. The written confirmation is what I rely on to receive benefits, rates and inclusions each and every hotel stay.