Changing your vehicle's wiper blades is an essential maintenance task. If you allow them to become too old, they'll eventually crack and degrade. This can be a major safety issue if you're driving in hard rain and your cracked wiper blades aren't providing you with a clear view. Changing the wiper blades on a Toyota Estima isn't difficult, but it's worth noting that the Estima is the Japanese model name for what is known as the Toyota Previa in North America. This will determine the part that you purchase for the wiper blade replacement.
Grasp each windshield wiper arm and pull it away from the windshield. The arms are mounted on spring-loaded hinges, so there will be some resistance. But the arms will stay in place once they're pulled all the way out.
Closely examine the small plastic adaptors that attach the blades to the wiper arms. Take note of the way each adaptor is facing, because you'll need to install the new ones going the same way.
Remove one of the old blades by pinching the plastic adaptor in the middle. Then pull the entire blade assembly off of the wiper arm while steadying the wiper arm with your other hand. The wiper arm is hook-shaped on the end. To remove the blade, just slide it toward the open end of the hook.
Repeat the previous step on the other wiper.
Open up the packaging for both blades. It should include the two blades, two adaptors that fit your car and the manufacturer's installation instructions for your blades.
Snap the two new adaptors onto the two new blades. While the process of sliding the adaptors onto the wiper arms is fairly universal, the process of attaching the adaptors to the blades depends entirely on the specific wiper blade manufacturer.
Install the first blade by lining up the slot on the adaptor with the end of the hook on the wiper arm. Then pull the blade toward the crook of the hook end. When you've pulled it all the way into place, it will make an audible click. Lower the wiper arm against the windshield when you're done.
Repeat the previous step on the other wiper arm.