A puppy's bladder has a limited hourly capacity that grows with age (roughly one hour of control per month, capped once adult). Every scheduled meal adds an immediate jump to the gauge; when a walk is due — or you take the puppy out manually — it heads for the yard and empties the gauge, counting as a success. If the gauge reaches 100% before it reaches the yard, it has an accident wherever it's standing.
- Bladder capacity — sets how many simulated hours the gauge takes to fill.
- Feeding interval — hours between meals, each adding fluid load.
- Walk interval — the fixed routine; the puppy also self-signals at 88% by heading for the door.
- Overnight hours slow the fill rate slightly and the puppy sleeps in its crate, but a schedule stretched too far still causes nighttime accidents.