As part of my floodlight maintenance how often should I tighten the screws
Every two years you should perform a visual check on every screw on each bracket, and make sure that every screw has not come loose compared to the original tightening torque.
Make sure that the floodlight is in the same position and that the tilt angles have not changed over time.
Depending on the floodlight line and model, side screws there may be 1, 2 or 3 per side. Check the installation manual for confirmation.
Do not tighten the screws on the glass screen - this could crack the glass.