It is my experience that draining the fuel regularly also has a maintenance benefit, particularly for aircraft that are picketed outside. This regular flushing keeps the drain clear of sediments and therefore ensures a prevention of drain leaks. I'm surprised that some have never found water or sediment in the fuel because it is extremely common for aircraft kept outside but not only. Much of the water found in the fuel may also be from condensation. It is good practice to always fill the aircraft to maximum for overnight parking if at all possible: W & B requirements for the next flight the following day may prevent this.