Install Synethic Underlayment for entire roof. Its a extra layer water protection in-case shingle blow off. ( $0.35 cents every 1 sq foots. Include garage.) Recommend roof slope below 6/12
Install Ice and Water Shield 3 foots along the roof edge. Install Ice and water Shield underneath valley. It’s a material to prevent ice dam leak. (Include Garage).
Clean the eavestrough twice. First before installation, and second after installation with leaf blower.
Inspect roof deck and replace any damaged plywood ( $55 dollars for each sheet 3/8, 4ft by 8 ft) Ask home owner before take any action.