Each time I give my car to the mechanics for major or routine maintenance jobs, my PETROL never, ever remain the same.

I once had an `engine-knock` on a full tank. By the time I bought the engine and replaced the bad one, I was told I needed to buy petrol to test run the `new` engine. Imagine my angst. Was some spirit test driving the `knocked engine` all this while?

Yesterday, I gave my car for wheel balancing and alignment and the full tank I had came to quarter tank within hours. This time I refused to pay the mechanic in full citing my missing fuel as deposit on account. But the man pleaded and I paid up.

But, am I alone in this? How do you handle this incidence when it happens to you?