I've got a 1993 306 XTDT with 106000K on the clock.
I think it's suffering from the classic shot rear subframe mounts.
It is up in the air with wheels off and if I kick the hub assembly down
sharply there is a knocking noise.
When underneath I can't make out if the flex in the mount is normal when hub
is kicked or if the knock is coming from there. It certainly isn't obviously
buggered.
Any tips to avoid a pointless renewal?
I know they have never been changed in its life.

Do they usually look okay when they deteriorate to the point of making a
racket?
I believe it is the front set on the rear subframe that are the usual
suspects. Is that right?

TIA