geeadamg:
You can check if your tracking needs doing by realizing if its pulling to one side or not - find a straight bit of road while no1 is around and let go of the steering wheel while its centre. If it does anything else but keep your steering wheel centre and you in a straight line then it needs doing.
Poorly adjusted tracking is only 1 factor that would make a car pull to one side. It could be caused by a worn suspension joint, steering joint, shock absorber or just down to a camber in the road or side wind. Therefore I wouldn't use this as method of diagnosis.
If you check your tyres regularly an indication that the tracking is out of adjustment would be if the front tyres are wearing more, both on the inside or both on the out side.