Another small point which is more a matter of how we speak is that I would not call a tank "fully mature" at six months but feel it about half ripe! Does a tank with plants and fish who change as they grow, ever get fully mature or are they still going through constant changes!
Every change I make is based on doing it slowly and watching what else is changed. I do not favor totally doing away with an area where I can keep a small "reserve" of good bacteria, just in case something major goes wrong in the tank. It allows me a bit more freedom to do anything like a major rearrange, etc.