Ten years ago, I bought a base 2014 MBA with 4GB of memory. It was a great computer. In 2017, Apple increased the base memory for the MBA to 8GB. When Apple made this change, my older MBA did not explode into a million pieces or suddenly become useless. I got three more wonderful years of use from my 2014 MBA before updating to a new 2020 MBA with Retina display. I was primarily motivated to upgrade by a new feature, not memory.