As someone that has built over a dozen hunting boxes and elevated stands over the years let me share that the single most important aspect to get right to lead to longevity is to be able to have weather tight seals for the windows. The cut edge of the wood around the windows and water intrusion to the inside will lead to a much shortened life of the blind. I never did develop a real good system. In my attempt to build them with a managable cost I devised my own plexiglass windows and flip up hinges, they worked great at everything except keeping water out and protecting the window cuts. The money I saved by not purchasing something that would really work was short lived as I had to replace walls on the blinds in just a few years. It actually ended up costing me more money and a lot more time to constantly be doing maintenece on the blinds.
Had I continued hunting I would have still built my own blinds but I would for sure have used these windows or something similar.
http://deerviewwindows.com/horizontal-slider-window/
I really enjoyed the comfort of hunting from blinds as a grew older. I would sit from before daylight to dark every day, never wet, never cold, very comfortable, lots of rooms for stuff, heater, food, water, multiple cameras. I even hung bird feeders outside of my stands to occupy my time during the day. I could close all of the windows and carry on normal cell phone conversations for work all the while not disturbing any wildlife around me. Deer, coyotes, turkeys all get very used to boxes, very quickly and you don't need them all camo'd up either.