As I've mentioned before, I (and many other patients) suffer from Raynaud's Syndrome. This syndrome is also known as "freaky stiff colored fingers disease." Raynaud's can lead to serious problems, as it makes it easier for people to get frostbite. This can, in turn, lead to the death of the skin at the tips of a patient's fingers or toes. That's obviously less than optimal.
I tend to prefer recyclable or reusable products. There are one-time use hand warmers that work well once, but must then be thrown away. I prefer to use a product I found that is reusable. It is called HotSnapz, and it is really really cool. All you do is snap a metal button and wham, you have a warm hands. To reuse, all you have to do is boil the handwarner until the solid crystals become liquid again. Very easy, very reusable,
The only downside to these handwarmers is that they are only warm for about thirty minutes. If you're going skiing all day, then this might not be the product for you. But if you're a patient with Raynaud's syndrome who needs instant warmth, it's perfect.
For those looking for a longer source of heat, I would recommend a more traditional, throw-away hand warmer. However, if you just need something to keep your hands warm on the way to work, or to stop Raynaud's from progressing, hotsnapz is the way to go.