I've been wearing these for trips longer that 1 hour. What a difference they make! For example, on the first Snakes to the Lake, I wore no ear protection and later at the end of the first night my head was aching! Since wearing these on long cruises, I have not had this problem at all.
http://earplugstore.stores.yahoo.net/holesmreearp.html
I must add that this past March I was victom of a nasty rear-end accident on the hiway driving to work. Since that accident, my ears have been ringing like crazy. I was examined by an audiologist who told me that I will have to live with it for the rest of my life. So, interesting it was a severe jarring to my neck (I was rear-ended, then hit the car in front of me - air bay deployment - I felt like a crash test dummy) that led my my Tinnitis no matter how much I protected my ears on long drives in our Cobra.