The quickest way to have a falling-out with travel buddies is to not sort out finances ahead of time.

You know your comfort level concerning money and your budget. Don't assume your travel companions do, even for themselves. Talk about it ahead of time. Discuss some of the options:

• Paying for everything separately.
• Maintaining a mutual fund for joint excursions.
• Keeping a running tally that gets paid at the end of each day.

Unless your budget is pretty loose, I recommend against the "tit for tat," or "I pay this time, you pay next time." Prices vary widely, and someone is going to feel over-charged.