I think one 0.1uF per chip is wise. As for the 10uF, I've not bothered before, but I suspect it depends on how long to wires are and the power supply. I would think if the wires are short, a 100uF for 10 chips would be just as good.Paul
That "somewhere" you speak of is the datasheet:"Supply Bypassing and WiringTo minimize power-supply ripple due to the peak digit driver currents, connect a 10?F electrolytic and a 0.1?F ceramic capacitor between V+ and GND as close to the device as possible. The MAX7219/MAX7221 should be placed in close proximity to the LED display, and connections should be kept as short as possible to minimize the effects of wiring inductance and electromagnetic interference. Also, both GND pins must be connected to ground."
something about consistent current.
Why did you not believe what I posted from the datasheet about the caps?