Yous should to try not to pee before going to sleep, and to try to fall asleep despite the need, or either to try "eacape" for pee later during the night, and not to wasp one of your "legal" pee breaks during the day
I have to disagree with this advice for a few reasons.
1.) I myself have a hard time falling asleep on a severely full bladder. Holding my bladder, in addition to being something I have a fetish for, also happens to be one of my "top 10" techniques for staying alert when working an exceptionally late, but boring, shift. I don't think inducing sleep deprivation is the idea here.
2.) If she were to start dozing off, she could leak, how her master feels about this aside; if I am choosing to commit to a sub-role, I would feel absolutely terrible about such an accident knowing it was something which better judgement and decision making on my part could have easily avoided.
3.) In truth, if she were to use "just before sleep" as one of her 3 breaks, it would work to her advantage as ADH production during sleep cuts urine output in half, effectively making her bladder fullness on waking 8 hours later the equivalent of having held only 3 or 4 hours during the day. If she can resist the urge to have her morning piss (despite the fact 1/3 of 24 hours has already passed) till say another 2 to 4 hours (so basically after breakfast as late as possible, and within an hour or two of starting her work/school/busy day), her remaining 2 breaks now need only be 6 to 7 hours apart. And bladder volumes will be roughly the same for each break to the ladies room.
4.) Add to this, resisting the morning piss is probably the hardest as for urgency, but the easiest physically. Thus making it both the most "do-able" physically; and yet the most meaningful in terms of submission to her master, and the most challenging in terms of a challenge she can feel good about herself for, at the same time.