That's good advice, but it must be mentioned that discipline (and attention) are like muscles, you can strengthen them, but you can also strain them to dysfunc

That's good advice, but it must be mentioned that discipline (and attention) are like muscles, you can strengthen them, but you can also strain them to dysfunction. A one-sided approach, where you're always "on" can't work, it needs to be intermittent. You have to pace yourself. In a way, discipline is to be able to do when you're not doing, and to be able to not do, when you're doing. This last point should ring true to those with tendencies to obsess and burnout (like me).