In theory, it is possible to wash once before morning prayers and this would cover later meals if one made an explicit condition for this, and protected his hands from touching things that would necessitate a second washing. In practice, the application of this is limited to times of great need only.

We learn the conditions under which it is acceptable to wrap ones hands in a cloth when no water is available for washing hands.

We learn about the need to wash off substances that form a barrier to formal handwashing for eating bread. We also examine when only part of the hand is washed.

Where a reviis of water is poured on each hand in one go then this removes any impurity from the hand and with the water used. The need to raise the hands, to stop impure water dripping back on the hands is also then removed.

We learn the requirement to raise the hands when washing them so that impure water does not roll back from beyond the wrist to the hand and undo the purification of them.

We learn under what conditions paint, ink, or rings can cause an interposition when washing hands.

We learn under what conditions something stuck to the hands is considered an interposition and would invalidate hand washing.