CHEMISTRY ---> why should only a few drops of indicator be used during any titrations

But you add the indicator once the amount in moles of the substance has been accurately measured (by volume) into the flask. Therefore adding water or indicator at that point won't affect the titration in terms of altering volumes of concentration.Your analogy is flawed, the comparison should be "titrating against half a flask of acid" or "half a flask of acid topped up with half a flask of distilled water" both have the same "amount" (meaning moles) of acid in them.

What is concentration? The number of moles in any given volume. So he was unclear. By saying amount, I took him to mean volume, not concentration, as he specifically said "titrations don't depend on concentration, just amount".

Marcus

But amount does mean number of moles. Where every measurement has a unit, moles seems anomalous in being a unit for a difficult to name measurement. However the measurement is generally taken to be called 'amount'. So amount is to moles as volume is to dm³.

The amount of a substance present does not vary with dilution. Given that indicator is added after the amount of substance is fixed by measurement of a set volume of a solution of a fixed concentration, the addition of indicator diluting the solution cannot be an issue.