Any stiffen suspension will always increase wear on attached standard compents. Your original top mounts and bushes etc were not designed for that kind of treatment. Add to this the fact that people are fitting stiffened suspension to bushes and ubbers that can be 10+ years old and no wonder they fail quickly.
If you're going to lower a car properly you fit the coilovers with all new bushes (polly ones would be best) in the wishbones and drop links. You should also at the same time renew the top mounts for G60 ones and a new set of ball joints and track rod ends. THis way everything is new and in tip top condition from day one.
This is the ideal way but as it's expensive, time consuming and if you were to get a garage to do it horribly expensive people don't. Then complain when stuff starts falling off.
I'd like to know what is breaking on these coilovers though. Are they leaking fluid, breaking springs or is it just stuck adjusters?
nick