@noelrap hadn't read it yet. :) I like the use of "are you writing a public library" as a guide.

I still lean toward private first, partly because I change my mind on names a lot and partly because I like to signal to the reader which parts of a class I considered interesting. And, yeah, from an OO purist's perspective, my classes are probably doing too much, but I feel like that path can lead to diminishing returns in a typical Rails app...