[tonythetarga]

Torsion bars usually work until they break. If your bushings are worn and allow the t-bars to rub (more likely on fronts) then those bars may have metal on metal wear and would need replacing. If your torsion bars break you will know as one corner will collapse.
Your shocks are probably gas filled so you may not see evidence of leakage. If your car has all original rubber bushings, I'd start there....BUT doing the bushings will be a project that will lead you to inspect the t bars and have the shocks checked. Do this all at one time if you can so when finished, you can do one alignment and one corner balance.