It really depends on a lot of factors regarding the bed staying level over time, how often it's used, what temp ranges you're putting it through how much the machine itself gets moved, replacing the removable flexible build surface for easily removing parts. Not as though I needed to level my diy one made of acrylic and threaded rod every time but it was often enough and failed prints infuriating enough to justify the upgrade. With mesh bed levelling I just don't really have to think about it much anymore can treat the 3d printer more like a 2D printer just hit go and expect good results.