I like to have a few (maybe 5-10) chunks ready so I can pick up my laptop and start working any time, and not have to decide what to do next. This helps when I'

I like to have a few (maybe 5-10) chunks ready so I can pick up my laptop and start working any time, and not have to decide what to do next. This helps when I'm low on energy - I just pick something easy from my list and I can still make progress. But you're completely right: planning everything in detail at the start would be suicide (at least for me).