So I have been told though I have not seen it was in the days where pilots were trained on T11s and then fly solo on the F5. The T11 had a single fuel gauge calibrated in lbs up to IIRC 1,400 lbs for the four wing and one fuselage tanks. The F5 had five individual gauges calibrated in gallons. These were mounted in front of the pilot behind the control stick.
The observation was that when a student did his downwind checks in the circuit there would be a frantic wing waggling as he moved the stick from side to side adding up the gallons to make sure he was above minimums. This was because the aileron response was far quicker then a T11 and looking inside he wouldn't notice.