Really depends how you're defining "need".

Will you die without it?

Will your life as you know it end if your next phone has 8GB instead of 12GB?

You need 8GB at the very most, which isn't out of reach for any consumer. If you need more, then you are a professional and can afford more. Or you are a hobbyist, and your hobby doesn't deserve any subsidies from the hard working tax payer.