There is one question I ask before starting anything new, and it has killed more of my bad ideas than every plan, spreadsheet, and strategy session I have ever run. The question is simply: what is the why. Not what will we build, not how, not when. Why does this deserve to exist, and why us, and why now. It sounds almost too simple to be useful. It is the most useful habit I have.
I came to it the way most people come to good habits, by repeatedly suffering the absence of it. I have started projects that were technically interesting, commercially plausible, and completely pointless, and the common thread was always the same. Nobody had made me answer the why out loud before we began, so we discovered the emptiness three months in, expensively.
The why is a filter, not a formality
Most teams treat purpose as a box to tick, a line at the top of a document everyone skips. I treat it as a gate. If we cannot give a clear, specific, slightly uncomfortable answer to why this project should exist, we do not start it, no matter how exciting the how is. An exciting how attached to a weak why is the single most expensive thing a team can chase, because it feels like progress the entire time it is wasting your months.
A good why has a particular quality. It is specific enough to argue with. "Customers want this" is not a why, it is a hope. "This specific customer keeps hitting this specific wall and pays us anyway" is a why you can build on.
An exciting how attached to a weak why is the most expensive thing a team can chase. It feels like progress the whole time it is costing you.
Why it matters more with a small team
When you run several products with a small team, the why is not a philosophical nicety. It is survival. With fifteen people, every project we start is several projects we cannot, so an unjustified yes is really a hidden no to something better. The why is how I keep us from drifting into work that is busy rather than important, which is the quiet way small teams fail. This is the same discipline that runs through how I prioritize across everything. Choosing is the job.
Asking it of myself, too
The hardest place to apply the question is inward, on the projects I personally want to do because they are fun or flattering. The why is uncomfortable precisely because it does not care what I find interesting. More than once it has talked me out of something I was excited about, and every single time, with a bit of distance, it was right. A clear no in week one is a gift. A muddy yes that unravels in month four is the thing the question exists to prevent.
So I keep asking it, on everything, even when it is annoying, especially when it is annoying. The discipline is not in having a good answer. It is in being willing to not start when the honest answer is that there isn't one.