I have a 2007 Infiniti M45 with 200,000 miles, car runs like a charm but I am having a problem with the rear alignment. Passenger side rear is wearing tires crazy fast. Either my local shop is blowing smoke about my specs or it is not holding alignment. My car knowledge is limited but I try, I am new to this forum would appreciate any tips.

It is possible that shop, like many shops, does not have the skill or maybe their equipment is out of spec. Similarly, At my oil / filter change last week, My tires are now ready to be replaced. They read 3/32 on all but the passenger rear which is at 2/32. I suspect that I must have driven over a pothole or maybe snipped a curb that knocked the alignment off on that corner. When they install my new tires, they will do an alignment and I will be sure to look at all 4 corners to see if that wheel is slightly more out of spec than the other 3.
BTW ... there are 4 tire shops near me and NONE of them have ever done the alignment properly. I only use my dealer now and they have never missed on the first try. yes, it's about $40 more expensive but worth it since it's $40 extra I spend maybe once per year or less.

Thanks for the reply but it is only one tire with a bad alignment all other tires wear normal. Because of the way the M45 sits and my negligence I did not notice my tire wearing so unevenly until it’s too late. If it was all 4 I would blame shop but being just one tire I think there is a bigger issue.