Daylilies last a day. No amount of water in a vase is going to make them last any longer than the day. If no one is going to be in the garden to see them, you may as well bring them inside. If they are still pretty at dusk, you may as well bring them inside. If you snap each flower off carefully at its base, you can leave all the buds there to develop and open another day. You can just lay them anywhere, but after coming to my office the next day to find wilty maroon or orange or yellow stains on my paperwork, I took to laying them on a plate. And if your day is not in the office but on the road? Take them along. Line the dashbaord. Enjoy them as you drive. Take the beauty with you!
What a way to make a great day nicer!