I use a rotary cutter and ruler and always give an extra 1/2 inche per yard when measuring.. When I get a bolt of fabric that is printed off grain, I will add enough to compesate, sometimes up to 2 inches on each end. Oh yeah, at no extra charge.
And if I am at the end of a bolt I give any thing less that 1/4 yard to the customer at no charge.
It always bugs me at Hancocks when the measure the end of the bold to the inch and charge me for it...