A couple things about windows, My company does window installation on every single project. We don't do window replacement . There are a couple of things we consider, sealant joints are never used as a primary means of preventing water intrusion. Confirm compatibility of sealant with everything the sealant comes in contact with. On a Project I recently took over the compatibility issue was not addressed and the contact of the sealant and the soft flashing behind it caused a chemical reaction that caused the membrane to liquefy... I'm guessing the repairs on the building will run 50k. None of this may apply to window your replacement. If I were having mine replaced, I would get a copy of the manufacturers installation instructions, confirm they are being followed and test the windows upon completion of work... Window testing standard testing values should be available on the Manufacturers website. Dont just blast them with a water hose...... good luck