not a hard job to do at all IMHO. remove blind. remove screws from "L" brackets. remove old covering (small flat screwdriver and/or needle nose pliers will help to get staples out. On some material it is strong enough to just pull on the material and staples will come out.) Cut material to fit valance, install staples to hold material in place and remount all.
Takes a bit of time but worth it every time you look at finished product.
Other option is to pay someone about $150 to $250 to do each one for u.