Sun protection is such an important thing and something I'm very vigilant with. My boys don't appreciate it at all but they will when they're adults and don't have sun damage!
Social Soup sent me a My UV Patch to and I loved it. They have an app at you dowload, then you scan the patch every few hours and it tells you if you need to apply sunscreen. I found it really interesting to learn how often I need to reapply my sunscreen. On a really hot day (36 degrees) I needed to reapply every hour! I don't usually go in the sun when it's super hot, but if I do I certainly don't reapply my sunscreen every hour.
I was pleasantly surprised to discover that my sun exposure wasn't as bad as I expected. I do my best to stay covered up and out of the sun, I apply sunscreen every time I'm in the sun, but I assumed that I'd still have quite a lot of inadvertent sun exposure when I was driving etc. Turns out it's not nearly as bad as I though it was, which is great.
Here's how it works. You stick the patch on the back of your hand, scan it with your phone and then rescan it every time a reminder comes up. The app will tell you if the UV index is high and also tells you when you need to reapply your sunscreen. La Roche-Posay say that the patch lasts up to five days, mine lasted seven before I removed it. It was still fine and could have lasted longer but I felt I'd learned enough so took it off.
These are for sale but I'm yet to find them. My local Priceline doesn't have them, but it's worth checking with your local stockist to see if you can get hold of one.