Take it from a person with dry, itchy, burning eyes that happened as daily occurrence. This statement is so true to fact. I was one who looked and looked for that one drop that would be comfortable and last longer than 1 hour. With so many different brands and types you must be careful not to make your condition worse. There are artificial tears with preservatives for (longer shelf life) and preservative free ones you can use more often if needed. You have antihistamine eye drops for allergy sufferers, but these have medications in them. There are also prescription eye drops for glaucoma, pink eye, and many different eye infections that have even more medications in them that need to be used as directed. So many things to think about before you drop that drop into your eye. I used generic and brand name drops and yes sometimes on an hourly basis. Then I started to use Oasis Plus drops from Oneota Valley Family Eye Care. Behold I used twice a day for 3 months. Now I can use once a day or twice a week usually before bed. I love that they are preservative free. This way I can use as often as I want or need. As always, read the directions and side effects on the labels. And then, if like me, when you are getting that eye exam talk to your eye doctor for help. My eyes have never felt better. – Dori F.