4-5 gallons of rootbeer

I made my first batch of rootbeer from a concentrate the other day, just a 2 liter. The more I read about making soda the more I read about individuals making 4 or 5 gallons of rootbeer, but I also keep reading that I should consume it within a few weeks. I am not sure, but 5 gallons of soda in 2 weeks seems a bit much, almost a liter and a half per day. I don't have a kegging system, just plastic bottles. I could make the space to store the rootbeer in the fridge, but I was wondering how you all do it. If I make 5 gallons can I keep it refridgerated for longer than a few weeks?

I've never made soda, but I do know that some of the guys who talk about making a lot have multiple kids.