I want to do this and open it for our 25 year. I think this would be done during the "ceremony". Read the letters, place them in the box. Have two bottles of wine. Exchange a drink and place the other bottle in the box. Expressing that it tastes good now(love is good now) and will only get better with age.
VERONICA... You need to register. I didn't register for my wedding and I regret it all the time. This list is great, minus all the alcohol-related stuff you won't need. Register. If you need help, I will gladly help you!