When is alignment needed determines, I mean besides having the dealer put it on the "alignment machine" and making measurements?
If the tire wear is uniform and the car tracks well on a level paved street/highway then no alignment is needed. Is this a sufficient test for alignment need? Of course seeing the tires worn out due to alignment problems is costly too... but in my case my Forester has abouot 40K miles and I've replaced the tires. The original tires do not show uneven wear.