These are bulbs. There is only one set of stems and flowers each year. Keep them watered and fertilized until the foliage shrivels and then cut it off. If they are going to be kept in pots, they will need bigger pot(s) with fresh soil before the next growth and bloom cycle starts next spring.
Don't cut Lilies back further than 1/4 of the stalk after blooming. The bulb needs the food and recharge from the rest of the foliage to prepare for next year. All I do is snip off the seed pods and leave the rest. If you lop off Lily stems too low and too often, it will weaken the bulbs to a point where they won't bloom any more and may die. But if they are a true tiger type with round blackish stem bulbils in the leaf axis all along the stem, you can also propagate a ton of new ones.
