I imagine it's simply to put a stake in the ground. The exact number (2 or 4 or 5, etc.) is not important. Three years is long enough that it can probably inclu

I imagine it's simply to put a stake in the ground. The exact number (2 or 4 or 5, etc.) is not important. Three years is long enough that it can probably include ramping up time, pivots, mistakes, tuning, etc. while not being so long that he's going to be an old man and/or unable to enjoy it, or have follow-on goals be pushed out too far. Regardless, one year is unrealistically too short. Twenty years is depressing. So pick something in between.