Jade plants rarely need to be re-potted more often than once every three or four years. It's best not to transplant them unless it's absolutely necessary, so if they're happy in their pot, leave them be. However, if the growth seems to be stunted, or if you see white roots beginning to show on the top of the soil or through the drainage hole, it may be time to re-pot your jade.
Select a pot that is one size or two inches larger than the current pot. Don't choose a larger pot than this because it will allow water to collect near the roots which can lead to root rot, the moral enemy of succulents. For this reason, be sure the pot has drainage holes in the bottom.
Make a planting medium for the jade by combining half regular potting soil and half potting soil made especially for cactus. If you don't have cactus potting soil, you can mix regular potting soil with sand.
Hold the base of the jade carefully with one hand while you pull the pot off with the other hand. You may need to thump the side of the pot with the base of your hand to loosen the plant. If the jade is very large, ask a friend to help you.
Check the roots for any signs of rot, which will be squishy and may smell funny. Clip off the afflicted areas, but don't remove more than 1/3 of the root system.
Fill the new pot about 1/3 full with the planting medium and carefully set the jade into the pot. Adjust the level of planting medium to be sure the jade will be about the same level in the new pot as it was in the old one.
Water the plant until water runs through the bottom of the hole. Add more potting soil to the top if the soil settles too much. From this point, treat your jade the same way you did before it was replanted.