Deciding Fuse Size?

Hi,

I was just wondering on how would you go upon diciding on what fuse to use when wiring up electronics to your car?

ei, neons, leds, amps,

is there a formula that tells what size to use?

thanks,

its not all that critical, you are trying to prevent a dead short in the wire, the equipment should have its own protection (or recommended fuse size) to protect the internal circuitry from excessive current draw.