If sediment builds up, you may need to replace the radiator altogether. Replacing a radiator costs five to six times as much as simply replacing engine coolant. Have transmission fluid changed every 15,000 to 30,000 miles. Doing so will strongly increase the chances that your transmission will last the life of the car and that you won't have to go to the expense of installing a new one. Tire rotation should be performed every other oil change - about every 6,000 miles.
Rotation substantially increases tire life by dramatically reducing wear and tear.
Replace shock absorbers and struts every 24,000 miles or every two to four years. Driving with old shocks and struts can wear out your tires, ruining the treads and causing poor handling and performance. Shocks and struts are significantly less expensive than new tires. Consult your owner's manual and your automotive technician. These guidelines are general rules of thumb.