After reading through the FAQ's as well as replacing various front end parts on several previously owned volvo's, I have come to the conclusion that some things never change (always wear out). They seem to wear out together and should be replaced together.
I just today rebuilt my 90 740 with the following new parts.
-struts
-strut bearings
-bellows
-ball joints
-front control arm bushings
-inner and outer tie rod ends
-alignment

Car was hard to turn at just above idle like in a parking lot or out of the drive. It now turns like a dream. I believe either the old bearings or the old ball joints (or both) were so stiff it made turning very difficult. Road bumps are what they should be now. The car even brakes more evenly. I should have done this a long time ago.

I think sometimes we only replace struts or tie rods or whatever and see very little difference. If there is over 150K miles like on mine and nothing much has been done, I would go for the treatment above. You want regret it.