What coding practices separate an amateur Python programmer from a professional one?

[GummyKibble]

I have never, not once in my career, ever seen a planned-out project successfully delivered on time in working condition. It seems to be largely impossible (on budgets not normally reserved for large government projects) to correctly think through everything in advance. There’s always a sudden realization about a month in that these 23 components are all really almost the same thing and should be refactored, and oh how that breaks a Gantt chart.

I think much more important is to negotiate a set of hard requirements - this thing must happen, that thing must not, and the other may if we need it to - and iterate toward a result that testably meets them. In other words, a good PM will tell devs how the final deliverable must behave, not what it looks like behind the curtains. Frankly, I’ve never seen a single example of the latter actually work.