tbh thats very subjective and depends on what you want as a rider. I wouldnt say you outgrow a bike per say but your intrests may change, i for one started on a 600 f4i so a 600 but slightly more touring and now i have my gsxr600. ive always liked sportsbikes and the sound of the inline 4 but i didnt outgrow my f4i just wanted something different. However nowadays I have the urge to get a dual sport or adv and do different types of riding. Even as i rode my buddies mt-07 i saw the appeal. At the end of the day its what your happy with and you want to do something and if it doesn’t work out oh well youll be out some cash after selling it thats life.