Back to the topic.
If you're flying your own aircraft regularly, I doubt most pilots are doing the calcs or plotting the graph every flight.
I've done the calcs and plots for my aircraft and know that my wife and I, 25kg in the baggage area and 95L of fuel are under MTOW and within the envelope at all stages of flight.
So the 3 things I do are confirm fuel qty, actually weigh the stuff going in the baggage area, and then politley ask my gorgeous, stunning, love of my life what she weighed that morning π± π² π¬, If the numbers are within my limits, were good to go.
I know that 95L is going to keep the Rotax spinning for 5.2 hours, which is far longer than I can cope. We are typically on the ground again in less than 3 hours (longest to date is 3.5hrs).