Been at this since 1964. My expereince is that it matters little or none at all how long the stand has been in place before you hunt it.

Sure I have had deer cross my "walk-in" trail and spook ... but I have had at least as many times deer have crossed my track and never checked up.

It is playing the wind, and being stealthy about movement and noise that are the two keys to not spooking deer.