Went to the Post Office today to send a calendar to a friend in the USA. Postage cost more than the calendar. I was using the self service machine and the screen said to fill in a Customs Declaration Form. There were none there and no staff except for one person at the counter with a queue of at least 10 customers. I waited around for some time, but in the end I just posted the calendar without the CDF.
Will this make any difference to how soon it reaches it's destination?