Dunno about that, there are some videos showing some of that stash he left behind, large trash bags of film rolls stuffed in file cabinets and desk drawers, as I recall. Not exactly what most would consider "proper".Garry Winogrand used tri-x and often waited years before having exposed rolls developed.They were probably stored properly though!
The image starts degrading very quickly, and the process continues until the film is processed. But on a pratical basis, a few months is generally no problem, when you start measuring the timeframe in years the affects start to be obvious. How bad the affects are depend on the film and the conditions.