[Quicksilver]

A torsion bar doesn't really wear unless something else fails. It might snap but that is an obvious failure. The rear doesn't have an issue with this.

On the front the A-arm bushing can get badly worn and cause the A-arm tube to rub on the T-bars. That can cause squeaking and if there is any visible wear on the bar then it must be replaced. (after the bushings are replaced!)
It might be possible for the splines to wear if there was a huge corrosion problem but replacing the bars wouldn't help that.