The 210s have the worst reputation for fuel exhaustion accidents.
In the Cessna Pilots Association Course, there is a flight planning exercise. Some pilots remember to look in the supplements sections for the various changes to their particular aircraft such as intercoolers, oil coolers, speed kits, STOL kits, upgraded engines, tuned exhausts, air conditioners, and other STCs that can greatly change their fuel burn. Others get that lesson when we have co-owners do the plan and they come up with different answers.
Most of the time, in flight training in flight training aircraft (C172/PA28), I am quite familiar with the aircraft and know that no matter what I do to the plane, power-wise, I have exactly 4 hours and 30 minutes of fuel. I land at 3 hours and 30 minutes.
On the 210 series, it gets very interesting. Two hours of fuel burn plus an FBO mis-fueling (very common) might mean an off-airport landing depending on the direction of the RADAR vector. If it is an unfamiliar 210 flying anywhere beyond 2 hours, you betcha I am planning the flight to the nth degree including the weight and balance for landing calculations.
The electronics are nice on the ground. During the written, do the calculations twice, three times if you like. In-flight, nothing beats the manual E6-B. No batteries, no button punching while in turbulence, and you can get several answers from one ground speed.
Fly SAFE!
Jedi Nein