as ever trod shoe-leather

act one's age, not one's shoe size

Synonym of act one's age (“to behave in a mature manner; to avoid being childish”).

if the shoe fits

Ellipsis of if the shoe fits, wear it.

if the shoe fits, wear it

If a description fits, it is probably the case; if an insult accurately describes you, you must bear it; if you take offence at an insult that was only implicitly directed at you, you admit the insult is true enough to be recognizable.

leather working

The technology of making products from leather.

pebble in one's shoe

A small and bothersome issue that may worsen over time.

put the same shoe on every foot

To attempt to apply a single solution to different problems.

shoe-leather

The sweat of one's brow; effort; investigatory effort.

slap leather

To make a quick motion to draw one's handgun from its holster, especially in a duel in the Old West.