What type of history are you doing? There are 3 types VCAA have.
I can speak on History - Revolutions and for that as many quotes as possible is preferable, but if I have to pick a minimum number I'd say at least 5 per revolution. But I would use quotes that fall into multiple categories to be useable in a variety of questions.
An example: "The machine gun became for them the principal instrument of political persuasion" -Richard Pipes
Can be used to support an answer talking about Bolshevik power, the use of violence, intimidation, how leaders consolidated power, the Constituent Assembly, Lenin's methods, etc. These types of quotes are very useful to remember because they can applied to a lot of questions.
