a change: something fresh that takes the place of what was there before, whether clothing, a work shift, or a turn in someone's situation
The picture behind this word is a turn taken. Something steps into the place the last thing held, so the place stays filled while what fills it is swapped out. That single picture is what lets one word cover a fresh set of clothes, a crew of workmen rotating home, and a man waiting for his circumstances to turn.
Clothing is the everyday case, and it explains why the word almost always shows up in gifts and prizes. To hand someone a change of clothes is to give a whole outfit to put on instead of what is being worn, so the gift is counted in sets: thirty of them for Samson's riddle, ten from the king of Aram, two pressed on Gehazi. The word names the swap rather than the cloth, which is why a separate word for garments stands next to it every time.
In poetry the same picture goes abstract, and the shift is small. Solomon's laborers went to Lebanon in rotations, a month away and two months home. Job, counting his days like a soldier's term of service, waits for the turn that will end it. On the usual reading, the comfortable people of Psalm 55 have never had such a turn come at all: nothing in their lives has ever been swapped out for something worse, and so they have never had reason to fear God.
It is not the word for a trade. An exchange, where one thing is given up in order to get something else in return (תְּמוּרָה), turns on what each side ends up holding. A change in this word's sense turns on the place being refilled: the same body, the same job, the same person's situation, with something new in it.