Engine Balancing... Voodoo or Should do?

It seems clear to me that engine balancing is important. The confusion seems to be, to want extent of balance is necessary or required for engine longevity and performance?

There seem to be so many different options for engine balancing. Some shops say they use x, y, z method other shops say a, b, c. Everyone seems to balance different parts. Some say every part that spins on the crank should be balanced others say only certain parts need to be balanced.

A local shop says I need to balance

1. Crank
2. Flywheel
3. Pressure plate
4. Connecting rods
5. Pistons
6. Fan hub
7. Fan

At Aircooled Tech that they require the following parts for a proper balance
http://www.aircooledtechnology.com/index.php/dynamic-balancing

1. Crankshaft
2. Crankshaft gears, spacers and retaining hardware (do not install them on the crankshaft)
3. Flywheel
4. Gland nut or flywheel bolts
5. Pressure plate
6. Front crank pulley 356 and 911 (Cooling Fan TIV ONLY)
7. Connecting rods
8. Connecting Rod bearings
9. Pistons& pins
10. Piston rings
11. Teflon buttons/wrist pin clips

In up and coming updates I plan to answer the following questions.

What are the tell tail signs of a good balance job vs a bad?

Is there any way to confirm a good balance job?

Also what are the right questions to ask to screen out the posers from the real deal?

On top of that I also read about volumetric balancing. Is this necessary?