three times a week is the least you should be rolling or doing standup if you really want to excell and exceed
Some people just don't have the time.
I think I will start with BJJ soon (twice a week) and continiue with Boxing (once or twice a week). I would love to train BJJ at least three times, Boxing at least two times and lift weights once or twice a week.
If you have enough time, but can't go to the gym, you can work on power, speed and endurance. People that do martial arts often deny it, but I still believe physical attributes are a BIG part of fighting.
However, if you can, you should train more BJJ.
In Boxing you have like two situations: Your opponent is a southpaw or orthodox.
In BJJ you can have the mount, knee-mount, turtle, guard, halfguard, side-control, get mounted, turtled, knee-mounted, be in somebody's guard, half-guard, guard, ...
It's so fucking complex. Up to now I've done No-Gi twice and Gi once and it seemed to me like the Gi makes it even more complicated.