In my company flightplans are calculated 180 minutes prior to EOBT and use the latest available forecast winds. As Intruder says above we have the ability to download winds directly into the legs and descend forecast page and do so at least once a flight, on longer flights more often. Those winds are then from the latest winds aloft info and on the planned cruise level and descend winds for FL310/200/100. Updating descend winds just prior TOD or during initial descend will give a very accurate wind profile resulting in an on speed ECON descend until vectors are given. Age of the wind data depends on update cycle of that information, downloading always gives the latest info.