I voted "Basic Plan". Here are some examples of my 5e pcs and the level of planning I did for each:
Friendo, gnome wizard: Didn't plan anything at all, high stat was Con, at various points considered multiclassing with monk, barbarian, etc. Never did. No plan at all, really.
Sax, dragonborn fighter: No plan for character build, but planned to carve out a LE tyrannical kingdom.
Inasaidia: Planned to be a cleric/fighter/magic-user in the classic style (except human). So far so good- clr 3/ftr 1/wiz 2. What's next? Every level is a big debate, but right now, wizard 3 looks good so I can take the spell darkvision so our party can go lightless. We're in the Underdark- I suspect we might be playing Night Below, but I am not sure (we've had some boxed text, we're in the UD, but I've never read it, so I don't really know... fingers crossed!).