Suppose you are a perfect utilitarian of some kind. You also live in a world where the utilities associated with your actions are well worked out. You can always spend $1 to save a life, which is worth one million utilons. You can also spend $1 on a cup of tea, which is worth three utilons, and will also make you a little better at working all day, producing $30 of extra value. So tea is a slam dunk.
However you also have a friend who would like to drink tea, and it will also make her $30 more productive. However your friend is not a utilitarian, but rather some kind of personal leisure satisficer, who will spend her dollars on magazines. You have an opportunity to buy tea for your friend, when she cannot buy it for herself. Do you do so?
Yes. Unless it is a very one-shot friendship, she will likely remember your generosity and buy you tea another time, perhaps when she is the one with the unique tea buying opportunity. So it is roughly as good to buy tea for her as it is to buy tea for yourself. It doesn’t matter whether your friend’s resources are to be ‘wasted’ on goods that you don’t care about, or whether her pleasure in a cup of tea can compare to the value of the human life foregone to buy it. It just matters whether the two of you can cooperate for mutual gain.
I think people often feel that having friends who are worth more than a thousand distant strangers is a departure from some ideal utilitarianism. Or that it is only ok to have such friends if they share similar values, and will spend their own resources in the way you would. I claim highly valued friends are actually a natural consequence of utilitarianism.
There is a difference in how much you care about your friends terminally versus instrumentally. On utilitarian grounds you would care about them terminally as much as any stranger, and look after them instrumentally so that they look after you. However, caring about each other terminally seems like a pretty good arrangement instrumentally. If two people with different goals, who are cooperating instrumentally, can exchange this situation for one where they both know that they truly share a compromised set of goals, this is a win because they can now trust each other. Also, humans care about being cared about, so trading real caring produces value in this way too, without any real downside. So arguably any real utilitarian would end up really caring about their friends and other allies, much more than they care about people disconnected from them.