Basic rules for baring lines left and right

Baring lines left and right and letters like i or 1 could you give me a few basic rules at present I am putting them about one lines width from the edge of the letter, except commas and periods Asterisks etc where I move the right line out a bit. Do I make all the numbers the same width with the bearing lines so that they line up in a list situation.
Anne

The ten digits should all have the same advance width, even in a proportionally spaced font.

Erwin Denissen