Replacing windows on a rental

[Philip L.]

I am in the process of renovating a rental property and I need to replace eight windows upstairs and one window in the basement.

I have contacted four contractors to come on Monday and Tuesday to provide a price for installation as I presume I am better off supplying the windows myself, however this leads to a number of questions as my knowledge of windows is limited.

The windows have wood frames but the windows inside the frames are aluminum.

What would be the best option for replacement windows for a rental property?
Should I ask the contractor to measure the windows or if I am getting the windows myself should I try to measure the windows?
Any general advice for getting this completed? Things I probably need to know and understand.