Being a contact lenses wearer, eye drops are a must, and wearing extended wear contact lenses means that after a few weeks, the lenses tend to get irritating. Eye drops last 8 weeks according to all of the brands of eye drops I've tried. And with these being used in the eyes I don't want to take the risk and use them for longer just to save a few quid. This bottle was still half full after 8 weeks, so the remainder went down the drain. I've tried a lot of eye drops and there is little difference with most of them. Your eyes do feel fresher for longer with these, and you don't have the urge to rub your eyes as often but is that really worth it for the extra cost? These cost me just over a fiver, tescos own brand cost just under £3. For the few quid extra, it probably isn't. On the other hand you don't need to carry this around with you as you can freshen you eyes in the morning and at night, which is enough to keep your lenses fresh. The main ingredient in this is sodium hyaluronate, which is probably just another name for a purified type salt. This in effect is just a cleaner saline with a fancy name. It comes in a bottle that can be refilled, so you'd think it would be cost effective to get a big bottle of the stuff and keep refilling it. But with it lasting just 8 weeks you can't do that. The instructions aren't really clear but it doesn't take a brain surgeon to work out what to do with these. Overall, I would recommend these if you don't like watering your eyes very often, otherwise stick with the cheaper alternatives.