The damper is going to play a big part in the level of grip that the tyre it controls has.
Running one fresh damper and one with 20 years of wear, on the same axle, would not in my view* be optimal.
Plus, you're going to need an alignment after replacing the damper, which will actually be easier (and therefore potentially cost less) if you have just replaced the mounting hardware on both sides and it all actually moves when requested.
The damper is going to play a big part in the level of grip that the tyre it controls has.
Running one fresh damper and one with 20 years of wear, on the same axle, would not in my view* be optimal.
Plus, you're going to need an alignment after replacing the damper, which will actually be easier (and therefore potentially cost less) if you have just replaced the mounting hardware on both sides and it all actually moves when requested.
*Other opinions are available