[tome]

FWIW Haskell is the only language in which I've been able to return to code that I wrote six months later and still understand it.

[elbear]

It depends on how you wrote it. In general, I found it hard to understand point-free expressions (in the code of others, because I never used them).

[dllthomas]

IME, point free expressions are exceptionally clear when sufficiently simple, but get muddy fast. The inflection point is probably not too far from

    let rms = sqrt . sum . map (^^ 2)