Friend of mine sent me this email recently:
"If traveling with a partner or small group, how do you divide the costs? This is pretty easy if it's someone you're, say, married to — if you've already got shared money, it seems straightforward. But if you're going on a trip with, for example, a non-cohabiting boyfriend who makes about the same amount of money as you, so you want to pretty much split things evenly, how do you do it? Go Dutch on each restaurant check as it comes? Square up when you get home? Figure, I'll get this and you'll get that and it'll turn out close? I should note, in the specific situation I'm asking about, neither of us are crazy and both of us are decently employed, but I'd welcome your thoughts on what to do when a person is crazy, or someone makes a lot more than someone else."
I'm just going to give the married readers (and the divorced ones, too) a moment to finish laughing at the assumption that it is easy to share travel costs if one is married.
On to the question:
I would give my brother a kidney, cheerfully and without hesitation. I will not, however, play Monopoly with him. We both understand that doing that would only be fun for one of us. (At best.) Some friendships need that line around travel. However well you may get along at home, even close friends can be travel-incompatible, and there's nothing wrong or weird about that. Being unable to mesh on a hobby doesn't expose a fatal flaw in your friendship. Everyone doesn't travel well with everyone.
That in mind, there are some strategies that can smooth the path.
When traveling with one other person:
You asked, specifically, about a non-cohabiting person of pelvic interest who is, happily, a financial equal and not crazy. This is an easy one: Straight cash, homie.
Let us say you and the BF are going away for five days. You two need to figure out your total walkin'-around money* in the budget for those five days. Let's say it is $1,500. Each of you needs to contribute $750 in cash to an envelope marked "Vacation" before you leave. Now you have, between you, $300 a day. How you divide that — $150 each every morning; $100 each, plus $100 for dinner**; he carries the roll; you carry the roll; let's just figure out how we're gonna spend it all in advance, snoogums — is a ground-level decision between you two.
What's critical to this strategy is that you both agree that nobody is whipping out a credit card until you're back at home. If you both contribute the same amount, and you basically do the same stuff, the pool of money will divide itself evenly. (This method also works with a platonic co-traveler or a cohabiting romantic partner who brings the same amount to the table that you do.)
When there's an imbalance in income, suck it up and talk about it. It's different for a love interest than for a friend, obvs, but in either case you can figure out a solution that works for everybody well in advance. What's key is that you work it out at home, rather than in the field. It's much easier to refuse the "Helicopter skiing, my treat" offer when you aren't looking at the mountain. (And do refuse. Acceptance of that offer is very likely to come up during a Grade Five Plate-Thrower somewhere down the road.)
And if the person is crazy, dear heart, don't travel with that person. Shed them. If the sex is that good, stay in.
When traveling with a group:
This is more about setting expectations and managing potential conflict. It's still pretty easy to do if y'all cooperate. First, set some policies:
1) Everyone doesn't have to do everything. If four of you want to take in the $48 Monday Night Dragstravaganza Stage Spectacular, and for whatever reason two of you don't, no problem. The last two don't have to. There is no need to make it about money — maybe the two sitting out just can't stand Cher.
2 All meal checks (including a 20% tip) will be divided evenly by the number of people at the table. The efficiency of this is a breathtaking upgrade over everyone trying to work out what they owe from a 3-foot-long check and it'll all work out evenly over time. (Separate checks among two or three couples is fine, too, and sometimes works better for splurgy dinners, as long as you tell the server from the jump.)
3) Maintain a blacklist. Travel should be pleasant; having to worry about someone with a history of not pulling their own weight doing so again will spoil the trip for you even if they get it right this time. Be ruthless. It's your vacation.
In closing, here's my best rule of thumb for knowing if you are managing companion travel correctly: Everyone should feel, at all times, like it's probably their turn to pay.
*"Walkin' around money" is the trip budget excluding airfare, hotel, and anything else you pay for pre-trip (theater tickets, ski rentals, etc.) which you can divide evenly ahead of time.
**The yours-mine dinner strategy works especially well in Vegas if one of you is a gambler and the other is a shopper and each of you finds the other's hobby a little unseemly. (Hi honey!)