If rear control arms are replaced, do I have to get a 4-wheel alignment?

[TurnAround]

I would like to avoid the cost of an alignment. My feeling is, that there are certain suspension parts on certain cars where an alignment afterwards is required. Like, the after market front struts on my Z3 Coupe. They adjust in three directions. The car has to be aligned.

But, with the X5, most of its parts are 'non-adjustable'... so, why align after replacement? My rear control arms are slightly worn. I'm having them replaced. But, the new control arms won't be any different than the old ones.. so, why align?

Thoughts?

Would like to avoid the extra cost if possible.

Thanks folks!