The point at which you need to scale horizontally is (for most applications) when you hit data scale in terabytes. When this is the case, you probably have eno

The point at which you need to scale horizontally is (for most applications) when you hit data scale in terabytes. When this is the case, you probably have enough money to hire someone who knows what they're doing with databases in order to set up a migration properly - you don't really need the ease of use configuration features. SQL databases give data durability and transactions, integrity constraints, joins etc, which makes writing software a simpler experience (with a smaller chance of corrupting your data etc) which is generally a nice property to have when you're a small company that's moving fast and breaking things.