one of my window regulators was broken, and the other windows were also somewhat hard to roll up&down. i decided to replace the broken window regulator and prevent potential future damage of the others by replacing the rollers. (the replaced regulator came with new rollers.)
these plastic parts are somewhat prone to wear&tear&aging.
replacing these could be a reasonable preventative maintenance step (in addition to the otherwise necessary maintenance of the regulators), especially with somewhat "tired" window regulators (original cars, daily drivers, earlier restores).