I need to replace 3 wood casement windows that have seen their day. They are at least 25 years old and I cannot even tell what brand they are. I want to replace them with Marvin Ultimate casements. I thought to go with Replacement Inserts instead of entirely new windows both to save money, and also because there is millwork between each window that I don't want to mess with.

Two questions:

1. One contractor gave me an estimate for full tear-out. It was therefore significantly higher than the other two estimates which are for inserts. He said he thought I'd lose too much window glass with an insert. Each window is about 5' tall by 3' wide. My two other estimates were for inserts, and both those contractors said that "I wouldn't notice the small loss of glass from the inserts". Who is right?

2. One of the estimates for the inserts specified interior and exterior spray foam insulation. The other estimate for inserts specified fiberglass insulation around the perimeter of the opening. Should I be insisting on one type of insulation over the other?