Life expectancy of Rhodanthemum

alfharris8

I have had some Rhodanthemums in pots (due to Rabbits finding them irresistible in the ground) for about three years now.
They have performed brilliantly up to now but are not looking quite so healthy   although still flowering well.
Would they be classed as a short lived perennial that you would expect to need replacing every few years or might they just require a repot and some TLC? Thank you. 

Borderline

I would regard them like Lavenders. After a few years, they get woody, even if you prune back a bit in spring time. I find them very weak, and unable to take the winter wet. I suspect they do well with dry weather all year round. Others may have a different opinion.