This varies between the type of sprayer and the material you have been using (water-based paints are much easier to clean out than oil-based).
HVLP and conventional compressor spray systems are generally much easier to clean (around 10-15 minutes) as the material only touches the gun and doesn’t go through any hoses.
Airless paint sprayers often require more time to clean as you have to flush out the hose, piston, filters and gun. Cleaning an electric sprayer is not difficult, but can take up to 20 minutes due to the amount of water required and the extra parts that need to be cleaned.