Replace contorl arm on only one side?
 

I had my '93 325i in the shop and the mechanics reccomended and replaced a control arm on the right side.

It is common to only replace on of these, rather than in pairs?

thanks,
Todd

Most people replace them in pairs. The CAB (control arm bushing) at the rear of the arm should be replaced in pairs and if you replace an arm you probably need new CAB's and if you are gonna replace the CAB's and one arm you might as well replace the other arm. It's a slippery slope...