Some components are more susceptible to heat from a soldering iron than others. Reed switches are particularly delicate when you're learning their heat tolerances. In order not to burn up your components, use alligator clips on the component lead as a heat sink between the soldering point and the component. The alligator clip will "wick" away the heat allowing you to apply heat with the soldering iron longer. This technique is particularly useful if you have a short component lead or you're soldering to a particularly thicker wire.
If you have enough room you can use more than one alligator clip. I find alligator clips with flat "jaws" work best for this application.
If you're removing components from one board to use on another and you don't have the super cool, expensive rework station stuff, this is also a good technique to use to preserve the components for reuse. Even though you overheat them, they may still work, just not to full capacity, so avoid the problem all together and use alligator clips.