installation question

[seamaster]

Hi
I'm starting to gather information on replacing the windows in my house. Some of the existing windows are vinyl replacements and some I think seem to be original (50 plus years) but all rest in a metal frame. The only company I have spoken with so far said to do a proper job the metal frame should be removed and replaced with wood. Any guidance on whether this is true is appreciated. Thanks.

[flygirl]

Check into all substrate options in your area. There are advantages and disadvantages to all...vinyl, wood, fiberglass. Method for replacing old aluminum (assuming you do not have sloped sills) is the full cut-out method utilizing the nailing fin and then appropriate flashing/sealant/drip cap/sill pans as per AAMA specs. Finish off with choice of trim.