Suppose I do alignment now.

After 1 ~ 6 months, I will replace 4 tires. Will I have to do alignment again?




P.S.:

Reason I consider alignment:
1 or 2 months ago, I noticed shoulder wear on front tires. The shoulder wear was not symmetric. The outer left edge of left front tire wore more than the outer right edge of the right front tire.
I did balancing and rotation right away. But I postponed alignment because it was more expensive than balancing&rotaion.

Reason I consider alignment now:
I go to a mechanic for front brake job. Then I want to do the postponed alignment together to save time.


P.S.:
MB dealer askes $200 for alignment, but I can find independent mechanic or tire shop that askes half of that.
Is there much difference in the alignment job quality?