That three years is critical. You can pretty much overgow a tank in that amount of time of you don't crash or have failures. The next reboot is faster, around two years, because your tank is mature already and you are well past that first year crapshoot of a new tank. The first time that you have to destroy a Leng Sy Cap the size of a Thanksgiving turkey platter or a Ultimate Stag with probably three hundred branches and your heart breaks (those were my first two tear outs), you will never again want stuff to grow as fast as possible - this is the SPS'er equivalent of rooting for coraline to start to grow.
Every reboot you remove something that grows too fast or drives you crazy - this is where many abandon the birdsnest and montis. You also get better at positioning - stags at the bottom, tables in the open areas, etc.