Much of the information that exists online that pertains to pressure washing focuses mostly on the proper techniques from a cleanliness point of view. A big part of the reason why that is the case has to do with the fact that the main purpose of pressure washing is to enable the highest possible level of cleaning that humanity is currently capable of mustering up, but suffice it to say that this emphasis on cleaning practicality does not leave much room for other pieces of advice that you really need to start wrapping your head around.
For example, did you know that there is a fair bit of physical strain that can occur while you power wash your concrete walls and driveways? This physical strain will mostly occur in your elbow joints, so you should really focus on protecting these body parts in whatever way, shape or form you can think of. Elbow strain during pressure washing is a surprisingly common thing for people to go through, and it can result in chronic aches and pains later on in life.
You should avoid locking your elbow while you pressure wash since this is the position wherein the strain will be maximized. Not locking your elbow will prevent hyper extension and it can vastly reduce the damage that might occur over a few years. Leaving your elbow loose gives your arm a lot more space to absorb the shock and strain, and this will enable you to keep pressure washing for the remainder of your life instead of having to retire early. Think of it like a sport. Sports players need recovery and recuperation time, and so will pressure washing experts.