Beware vapor pressure! I switched from one gallon gas cans to the five gallon models last year. Haven't tapped into the five gallon cans all summer, as I have been rotating the smaller treated cans. Went to fill up the old lawn mower from the big can, and as always, I vented it to relieve the pent up fuel fumes. What I didn't account for was the heat of the day and the movement of the can from its shaded storage spot to the driveway. In this heat, it built up more pressure, but I didn't know it. Tipped the can, squeezed the handle and WHOOSH! Stream of fuel squirted out, and not much got in the tank. Yeah, maybe a pint of lost fuel, but that could run my Coleman stove for a good bit. Lesson better learned now than when the pumps stop working. Now I have to let the mower dry out before starting, which is a waste of time, and time is one thing you can't stock in bulk.