Casting a spell är en annan typ av åtgärder för att behålla en stavning, så nej, det finns inga av samma krav för komponenter.
Enligt de magiska reglerna för Concentration duration .
Concentration The spell lasts as long as you concentrate on it. Concentrating to maintain a spell is a standard action that does not provoke attacks of opportunity. Anything that could break your concentration when casting a spell can also break your concentration while you’re maintaining one, causing the spell to end. See concentration.
You can’t cast a spell while concentrating on another one. Some spells last for a short time after you cease concentrating.