When installing your window blinds, you should first know your window requirement. There are instances wherein your window opening's depth is wide enough for your blinds to be inside mounted and there are times where it can only be mounted outside. Know what is best and right for your window. Here are some tips:
For inside mounting, we have a 1 1/2 inch - 2 inches requirement. The depth of your window opening should be at least this wide in order for it to be mounted inside. Also, the width of the fabric of your blinds is only exact in the opening of your window.
For outside mounting, this is much safer because the brackets will be installed at the top of your window opening. It will also cover the whole opening and will not leave any gap at each side.