Gross Weight

Here is a topic that was of discussion at work today:

How much is too much over gross weight? For example.....the 172 has a gross
weight of 2300 lbs, but what if you are 2345 at time of takeoff.....is that
too much over, even if you are going to be burning enough fuel before your
first scheduled stop to be under weight for landing?

What about airframe age, prop age...etc? Does it make a difference on
decision to "carry a little extra"?

I know that when I was receiving training, my instructor once had me bring 2
male adults with me to a lesson. That put 4 male adults in a 172 with full
fuel. I don't recall the specific weight we were at, but we were over
weight. The airport we flying out of had 8000' of runway, and my instructor
had me doing pattern work. The aircraft was very clumsy, and made me really
work at flying it. I didn't like that feeling at all! It was a good
training day.

Anyway, it was a good discussion between a few of us at work, so I thought
it might make a good topic here.

Fred