Why should the input resistance of a instrumentation amplifier be as high as possible?

Input resistance answerRequired because sensors typically have a high or unbalanced source impedance. It is ideal to have no current flow through and OP amp therefore ideal to have infinite input impedance. If current is flowing through this could cause an error in the output. Please comment on this, not sure if correct.

Comment: If you are not sure about your facts, I see little point in offering an answer.

AnswerConnecting an amplifier to a transducer/sensor inevitably changes the conditions of the phenomena being measured. This is due, primarily, to the amplifier drawing, an albeit small, current from the transducer.

The higher the amplfier's input impedance, the lower the current drawn, and hence the less the disturbance to the original conditions.