In article ,
says...
chris writes:

That's a rather negative way to look at it!!!

Better safe than sorry, I say.

In a few days I will be
flying for 2 1/2 hours on a cross country. I will have 4 1/2 hours
fuel. That doesn't sound reckless to me!!!

If you really have the fuel you think you have, and if you really consume it
as slowly as you think you do, perhaps not.

Say 32 litres and hour, plus or minus a few - ain't gonna make much
difference.

Or to rephrase, how can a 32l/hr plane consume say twice that?

We know you're not a real pilot - well let me tell you that in the real
world, the rated value is used, *and checked* over time. And adjusted
as necessary.

I've flown a number of Cessnas and Pipers from different organisations
and they've all consumed the amount the manual tells me +/- sweet FA.

--
Duncan