I’m a big fan of the shared language of “MuSCoW” (pronounced Moscow typically).
In order of decreasing priority, you decide what you Must, what you Should, what you Could, and what you Won’t.
I’ve only seen it used in discussions relating to time-bound planning, so you could attach an implicit “… right now” to each of those.
Thanks for the pointer. Now I found a paper about buffered Moscow, which sounds useful: https://mse.isri.cmu.edu/facstaff/faculty1/faculty-publications/miranda/mirandabufferedmoscowrules.pdf
I like this article a lot. A related guideline I often use at work is: will this be harder to add in the future? When one person says “You ain’t gonna need it” a common response is “Of course you’re going to need it”, and “You don’t need it yet” is met with “but we’re already adding X, so we might as well add Y simultaneously.” These discussions aren’t really about predicting the future, but they look like it. It’s easy for a team to be split down the middle, and for people to hold no strong opinions either way.
But often people will agree that adding X doesn’t close any doors to adding Y, and it doesn’t make it harder or slower to add Y in future. The aggregate effort for Y hasn’t changed, plus we’ll know more if we defer it. I’ve found this is often an easier path to consensus, even if it’s an indirect path to YDNIY.