The workmanship is very poor and they cut corners at every step.
They use particle board instead of plywood for deck replacement.
They hammer the replacement deck particle board over the existing repair instead of cutting out the damaged area.
They do not nail down the protruding nails after the old shingles are stripped and do not remove leftover debris prior to shingling new shingles on the deck.
The do not use starter strip along the entire length of the perimeter of the edge.