After over a decade of being a legal adult, I’ve started to act like one. I’ve sunk into a bit of debt; I eat green vegetables by choice; and I go to bed early on a Friday night because what-a-week.

These things are all mostly functions of (a) having a more adult salary and (b) having a more adult metabolism*.
*which, ironically, has a tendency to act like a rebellious teenager, lolling about for days on end, doing nothing and getting stoned stones.

But there are other things involving adult salaries and metabolisms to indicate that I have actually arrived at adulthood. Mainly: group dinners and splitting the bill.

As a student, and even as a young adult, “splitting the bill” meant a 20 minute circulation of the bill folder while people ticked off items and smartphone-calculated their contributions and failed to make any note on the bill of what they’d paid in. Meaning that someone at the end had to spend a further 5 minutes doing a reconciliation of card slips and cash. Someone reasonably obsessive and tired of waiting 20 minutes already.

*clears throat*

But increasingly, my peer group are starting to act as though the only split that needs to take place is an arithmetical one: take total, add tip, divide by people present (and now-accounted for). It saves 20 minutes and, well, saving me time – saving me money.

It’s not a hard and fast rule – we’re still in that in-between stage where there are enough students and young adults at the table that the bill situation can go either way.

But we’re getting there.

Which will obviously cause some issues. Issues similar to the situation described in this Marketwatch article: “Must I split the check equally and pay for my friends’ booze?”

The issue, approximately, is this:

1. My friends have more fun than me when we go out (by ordering wine while I have tap water).
2. So why should I pay for it?

Diagram to illustrate:

To me, the answer is an obvious one. Just pay for your equal share of the bill already – we’re paying for the experience and the pleasure of everyone’s company, why are you getting so caught up in the food and beverage that accompanied it?

Whenever I mention this point of view in polite company, someone inevitably comes back with something like: “But what if you’re out with someone that orders five long island iced teas in succession, while you’re designated driver and sipping on a Coke Zero?”

To which, my general response is: “Are you trying to rule by exception?”

There are two types of friendship in this world:

1. Good friendships; and
2. Abusive friendships.

You don’t get miserly in good friendships because one time a bad ‘friend’ failed to offer to pay for his gigantic bar tab.

And for that matter, when we’re dealing with ourselves as individuals, we don’t need to talk legalities and treating everyone the same. Not at all. You treat your good friends well, and you treat your acquaintances by going Dutch – always depending on what you’re acquainting with them for.

Because Good Friendships Are Worth More Than A Third Of A Bottle Of Wine

The biggest issue I have with the pay-for-what-you-had advocates is reduction: they treat the splitting of the bill as a separate issue in itself.

But that is simply false. Dinners with friends do not exist in a vacuum: they exist in a context. We rarely demand equality from a friendship at every moment in time – all we really want is equality over time.

What I mean is:

• When you’re going through a tough time, you want your friends around for support;
• And when your friend is going through a tough time, you’re there being supportive.
• Those two things don’t usually happen simultaneously.
• What happens instead is a cycle of mutual investment – there are days when you invest and there are days things just tick along and then there are days when you get a payoff.
• Do you get bad investments? Of course. Where one party is less invested, or perhaps where someone wants smaller regular pay-offs while the other person tends to be more of a growth stock who is otherwise distracted but there like a flash in an emergency.
• But good investments are rare and worth more than what you put in originally (that’s why they’re good investments).
• Also, while we’re at it: friendships are not fixed income instruments – where you have a contractual set of obligations as defined by a contract and a coupon and a repayment period. No – that type of relationship is an economic one, and it exists between employer and employee. It is not a friendship.

So when it comes to paying for dinners and splitting the bill, demanding an unequal split based on what this person consumed and what this person didn’t? You’re doing one of two things:

1. You’re taking the friendship, putting it aside, and openly declaring that relationship is an economic one, where you expect to only put in what you get out at every point in time – including right this minute with the bill. Oh, and actually, this wasn’t a “dinner with friends” where at the end, we all pay equally for the full experience of everyone having a good time, so much as it was a coincidental meeting where each person was there for the primary purpose of eating what they ate, and drinking what they drank, and the company was incidental and the experience unnecessary; or
2. You’re declaring that any expectation that you might pay for something that someone else drank is an outrageous abuse of your friendship and how dare they and you feel strongly enough about it that you’re going to turn it into an issue.

And if you do either of those two things, then news: you’re the bad investment.

Are there exceptions?

Again – of course. When you’re with friends of differing income brackets, there is sensitivity required. Good friends offer to split out the wine if they drank it, or pay for their Long Island Iced Teas.

But even then, you need to ask the question: “How much am I saving here – and isn’t this something that I would gift into the friendship anyway?”

Because much like the parable of the poor woman with the two mites – if you have good friends that are already trying to be sensitive by splitting out the drinks, and you then tell them not to worry about it because you’ll pay your share, then the multiplier effect of that act has far greater potential than if it had come from someone else with more money.

It’s just a thought.

Rolling Alpha posts opinions on finance, economics, and the corporate life in general. Follow me on Twitter @RollingAlpha, and on Facebook at www.facebook.com/rollingalpha.