Tires: Strut and Tire Replacement, car repair shop, alignment problem

Question
I drive a Pontiac 2005 Vibe.  Okay, I went into the car repair shop for a routine replacement of a headlight and an oil change.  

I was SHOCKED when they told me I needed to replace my two back tires--because I had all four replaced with brand new tires last May (8 months ago), and had the tires rebalanced two months ago (the weights on the tires were off).  When I said that I had had the tires replaced in May, they looked at me, and then said, well, sounds like we need to replace the strut too.  I looked at the tires myself, they definitely need to be replaced, and an underlying reason for why the tires wore out so fast also needs to be explored.

So here is my issue: Is the strut so much the obvious underlying reason that they don't need to look at the struts on the car before replacing them?  It bothered me looking back on the interaction that they first told me I needed new tires, I told them the tires were almost brand new, and then they said I need a new strut--without ever going back and looking at the car.  I have an appointment on Thursday to bring the car in and replace the tires and strut--they are not charging labor, but are still quoting $800 total.  Could there be other reasons for the back tires wearing so unevenly?  I just want to ensure that I'm not getting duped, or replacing a part that doesn't need to be replaced.  

Here's my short-term vehicle tire history:
1) November 2007: Re-aligned tires.
2) May 2008: Replaced all four tires.
3) December 2008: Re-balanced tire weights.
4) Feb 2009: (Now-Recommendation of new struts and back tires)


Answer
Brook,

There isn't enough information for me to make an assessment.  I need to get a good description of the wear pattern, because it sounds like you have an alignment problem, and the wear pattern would confirm this.

You also didn't tell me how many miles on on the tires.  BTW Did you rotate at the proper intervals - 5K to 8K.

BTW Vibes are kind of known to get tire issues in the rear due to the excessive amount of camber they specify.  Add a little toe in and the tires could indeed wear quite rapidly.

I would go somewhere else and have them at least do an alignment - specifying you want the camber to be as little as possible, and you want the toe at the nominal setting.  If they don't agree to these conditions, find another place.