Perhaps the original reason for not setting batteries on concrete may no longer be valid, but I always set them off the concrete, usually on a slab of wood, to prevent any staining of the concrete caused by any residual acid on the cases.

 

advice I was given to not fill the tank totally full, like clicking and clicking the nozzle to fill the neck fo the tank. Just stop after the first click.

Some people still do it and will not stop. I was told that it does not leave the tank with enough room for the vapors to expand so the charcoal filter tank ( a coffe size can) gets soaked with fuel and causes problems in performance.