If you don't like sticking shiny bits of glass and plastic in your potting soil, you can upgrade the pot itself to get some self-watering freedom.
Instructables details how you can simply wrap a sponge in some wicking fabric (like a shredded t-shirt) and place it on a bed of rocks at the bottom of your pot. Refill the pot and go about your gardening as you normally would—except you won't have to worry about the soil drying out nearly as quickly as it did before.
Even if you're not planning on shunning your plants for days at a time, this could help out in extreme dry heat, too.
Converting Pots into Self-Watering Pots [Instructables]