Plan vs whatever happens: how do you make music?

[Mac of BIOnighT]

Inspired by a reply in an another thread: some musicians plan their albums or tracks ("I'm going to record an album in such and such style"), while others just sit down and start toying around following whatever direction the music decides to take.
Which is what you do?

[Thought Experiment]

I plan to the nth degree - I'll have an album 'concept' or theme, how many tracks, rough track lengths, titles, what style, what instruments (real or virtual). It's the only way I can make sure I make the most of whatever studio time I can grab. Like most of us, I have a 'day job' which pays the bills, plus other responsibilities (e.g. high-maintenance wife :D ) so I can't just leap into the studio whenever the muse perches on my shoulder. Having said all that, when I'm working on a track and it seems to 'want' to take its own direction, I've learned not to fight it ;)

[Guest]

i don't often make albums but make pieces and they are pretty much always composed beforehand - although what 'composed' means varies quite a bit. Typically I will have some sort of recipe for action, like consider the guitar fretboard as a geometric object and the hand as a shape upon that object. Use three shapes and two different tunings. Then I'll improvise on those instructions, record, and then edit - that gave this piece https://soundcloud.com/greghooper/th...nd-two-tunings
So that's a combination of a formal procedure that leads to a data set to then play with
whereas something like https://soundcloud.com/greghooper/one-forgets was pretty much fully composed - playing the root of the chord progression of pacabel's canon at a range of speeds, then playing guitar to that according to some instructions which I most likely have not kept but were about tuning the guitar at random, picking a single note then bending it to fit whatever I was hearing.