When do you know when you are ready to move up to a bigger bike?

Besides than having the money in the bank, skill wise how do you know you are ready to move up from a 300-400cc motorcycle to a 600-1000cc?
I know having a liter bike is everyones dream (if you're normal) but I dont want to jump too fast to a bike im not able to handle, and that instead of enjoying it I will ride it with constant fear of crashing.
Modern bikes have a lot of technology that allow riding them with more ease, but I've heard that liter bikes are far less forgiving as 300-400 cc bikes.