In reply to I have a question about purchasing typefaces.:
This is a really interesting question.
I buy two types of faces: workhorse fonts that I know I will use a lot, and specific one-purpose fonts for a specific project. In theory, I don't anticipate using the latter group ever again after the project is complete, although of course I always do.
I, too, am also very frugal. I rarely buy fonts at all. I have, in fact, very few good ones. Typefaces are very expensive, especially for a freelancer, as they have to come out of my profit. So I have to choose very carefully.
With general-purpose serifed text faces, I want, when possible, to purchase the whole family: Roman and italic in all optical sizes. (I almost never need bold or any weight other than regular, and I never need condensed or expanded versions. But if you're going to buy that much of the family, it's usually cost effective to get the whole thing. And sometimes the weights come in handy.) So every couple of years I will buy a new text family. And then I will basically use it all the time for a few years, until I really know it in and out, before getting another one. I stuck with Minion for three or four years; it was one of my first. It took me a long time to get bored with it. I don't usually buy text faces for specific projects, both because of the cost and also because at this point I probably own something that works.
Display faces are usually much less expensive, and I buy them more on a whim. Recently I bought two Laura Worthington faces just for fun, because they looked like they'd be a lot of fun to play with and they were very affordable.
So, to answer, at what point do I know I'm buying a typeface....
For a text family, I have to fall in love with it, and stay in love with it for a long time before I buy it. I admired Brioso Pro from afar for years before I finally ended up with two or three simultaneous projects where I knew it was perfect for all of them, and then I really had an impetus to buy it. I guess, I need to know in every case what I'll be using the font for, but if it's a text family = expensive, it usually takes a lot longer for me to get around to buying it. There are still plenty of text faces — Dolly, Quadraat, Seria, Rialto — that I think are beautiful and would love to have, but I know I'm not going to get them until I really have a project that needs them.
Does this help?
EDIT: You know, my advice to you might be to just go find a font you like, one that's not too expensive, and just buy it. Play with it. Don't worry if you have a use for it. It might be fun to just jump in.
EDIT again: I don't have an older brother, so I missed out on the kissing talk.
