B”H If someone eats enough bread to require benching at the beginning of a meal and they proceed to have a meal that lasts about 4 hours, and they are mindful to have very small bites of bread every hour or so (but small enough that this particular amount would not obligate benching, they are just trying to keep the original obligation to bench going throughout the meal because they want to bench)- can they rely on the fact that they had the original amount of bread 4 hours prior and this would obligate them in benching, or would they need to eat a “benching” worthy amount every 72 minutes or so to make proper benching?
A person that is in middle of a bread meal, does not have to eat bread every hour or so. As long as the person is still eating, it doesn’t have to specifically eat bread. As long as he was still planning on eating, and doesn’t go to a different place. This is something that happens at most weddings, the meal can last for a number of hours, and the person only ate bread at the beginning of the meal after washing.
O:CH siman 178.