Dylan Smith wrote in message ...
snip
My usual practise is to time AND check the gauges. If the fuel gauges
show less fuel than I think I should have, it's a cause for concern.
snip

I use a triple redundant method. I use time to measure fuel burnt
and burn from 1 tank at a time, but I also cross check the gauges. If
a gauge reads substantially less than it should at any point, that
calls for a landing to verify it manually. As a backup to all this,
I burn 1 tank for an hour, switch and burn the other tank until it's
nearly dry. If my calculations are correct, the second tank should be
empty right on schedule. If I have a leak or increased fuel burn for
any reason, the second tank will run out early and I still have plenty
of fuel in tank #1 to find an airport, land and check it out.

John Galban=====N4BQ (PA28-180)