The fixed stars
A year ago, I wrote Timetabling, about the benefits of specifically breaking down your entire day down into scheduled blocks. I said at the time that one of the main benefits of doing this is that it forces you to put more effort into planning and catches large-scale scheduling problems early. Those are definitely benefits, but there's another thing I'd like to cover specifically: a timetable acts as a frame of reference.
I covered some versions of this idea in High water mark, Bug vs feature, The Elo paradox, and Creative competition. In one way or another, all of those posts make the point that it's very important what you measure yourself against. A common problem is to set too high a standard and feel inadequate, but another problem is to set too low a standard and stagnate.
But as many ways as there are to get it wrong, having a frame of reference is still incredibly important. Without one, you often end up just doing things without knowing whether they're improving anything. Worse still, it's too easy to justify your actions in retrospect; if you have no frame of reference, you may as well just put a flag in wherever you end up and say "look, I reached my destination!" This is a degenerate kind of goalpost optimisation where you can just set your goals however you like. If you're doing that, what pressure would there ever be to do better?
I originally thought of a timetable as a kind of plan, or a goal: "I want to have this thing done at this time". But I now think it makes more sense to consider it a measurement. Not sticking to the timetable isn't a failure. After all, a timetable is an extraordinarily rigid instrument that doesn't take into account any kind of adjustments that you might need to make throughout the day. But it does prove particularly useful as a frame of reference: here's what you intended to do today, here's what you actually did. No more mystery in where the time went, no ambiguity in whether you achieved what you expected.
More generally, I think there is a lot of value in this concept of measurements that you observe without criticising. It's why I've continued to call out how many prototypes I've done each week despite having decided to stop committing to a specific number. The point isn't that I particularly need or intend to achieve a certain amount, but all the same I don't want to accidentally decieve myself about what the actual amount is. If I want to know how things are changing over time or draw inferences from my behaviour, that information should be readily available.
And if I want to place judgements and standards on top of that to push myself, great, but it all starts with having a reliable frame of reference.