Its kind of a relative thing and what you're building, where you're building it, where the wood came from, relative moisture, relative humidity, size of the pieces, type of species all play roles in it. Some don't acclimate at all, some use shorter time frames, many through experience will know what kinds of wood need what kinds of time frames to be reliable. I tend to bring pieces I'm going to use into my "shop" (shed) and they stay for at least a year before used in a build. I try to prepare pieces pretty close to final dimensions and then leave them for that time. If after a year, they're still good, my logic is that they will be fine after assembly and in service thereafter. Doesn't always work out that way though.
I'm a stickler for ensuring the wood I'm using is dry though - as in aged well and checked with a moisture meter. I'm also inclined to think that because pieces I use when I'm building are pretty small, and the glues are strong, if things go together pretty well, then tend to be in service pretty well. Of course, like above, it doesn't always work out that way.
When I did the flooring in my house, it sat in the room for a week in one case and two in another and they are both fine years later.
Curious to hear what others chime in with...
