Susan Heller said the following about packing for a trip:
"When preparing to travel, lay out all your clothes and all your money. Then take half the clothes and twice the money."
Interesting little quip! I have also found that we tend to take many more clothes than we need on a trip. I have begun the process of taking fewer clothes on recent trips and it is much better. I find that I can easily wear things several times (unless it is summertime and very hot, since I sweat a lot). My wife has even begun to take fewer clothes, and, now that airlines are a lot more conscious about baggage weight, it is more economical, too.
As far as money is concerned, trips are always more expensive than you anticipate. However, I try not to take a lot of money (cash), but rather try to charge as much as possible, since it helps with the bookkeeping after the trip, and since ATM’s are not always convenient. I also do not carry a lot of cash because I have heard many horror stories about people getting pickpocketed and losing everything.