I snip of the dead flowers and just leave them to die down and I store mine in a dry place for the winter, come spring I dress the top of the pot with fresh compost and start again.

I leave the bulbs in the ground and watch out for slugs when the new shoots start to come through in the spring.

You don't need to dig them up, as they are hardy.

Sorry mis-read that the bulbs were in the ground, a senior moment, apologies. You leave them in the ground as the others have said!!

Yes, true Lilies much prefer to stay in the ground.