l have a 2007 G35 6 MT , stock tires(Bridgestone Potenza 225 x 40 x 19 front, 245 x 40x 19 back), can anyone tell me how many miles the tires run for before replacing them? Someone told me it is around 1200 miles, l think that is absurd ! Please help me clarifiyng this.

Thank you in advance

No thats total crap.1200 miles? heh
Depending on the kind of roads you drive on and how fast you drive, usually you can replace them every 17,000 or so. But l think thats with the smaller tires, if you have the 19 is it will run down faster on roads, and probably should be done around 10,000 miles. It should not wear out any less than 10,000 miles though unless you really beat down on your gas pedal and burn through them fast.

Depends on your driving style. They should be replaced when the wear indicators are even with the tread. 12,000 miles is easily possible to wear high performance tires like yours out, not 1,200.

It all has to do with how you drive and how you maintain your tires. Rotate them every 5000 miles and make sure they have sufficient air pressure. Burn rubber at every light and they will last only 1200 miles.

Firstly.. dont rotate your tires, you cant rotate staggered tires unless you dismount them and cross rotate them since they are directional. (ie. take off the front right tire from the wheel, then put that on the front left wheel etc.). but that shouldnt be necessary unless you have some -camber from lowering the car.

About 20,000 under normal condition.

It depends on how you drive. If you drive normally, then:
It is around 15,000 miles.
If you drive fast or spin the tires, then it is much lower.

But Not 1200 miles. That is way too low.

FWD and AWD cars have their tires last longer.

l have a FWD car and l have driven 13,000 miles on my tires. And they still look new.