Also, stay away from bleach. It will eat away at the material over time, and your Gi won't last as long.
As long as you use bleach sparingly, like every 4-5 washes, your Gi's will last a long time. I wash my Gi's after every class. I have several that are >5 years old...they are in still in very good shape and look nice and white...thanks to the occasional bleach in the wash...