Every fluid runs on its own clock, and your owner's manual is the final word. As a rough guide, many automatic transmissions want fresh fluid somewhere between 30,000 and 60,000 miles. Coolant often runs 30,000 to 50,000 miles or two to five years, though some long-life coolants go further. Brake fluid is usually based on time rather than miles, often every two to three years, because it absorbs moisture whether the car is driven or not. Power steering and differential fluid vary the most from one vehicle to the next.
Then adjust for how you drive. Towing a boat, hauling a loaded trailer, idling in school pickup lines and running the A/C hard through a long summer all count as severe service, and severe service shortens the interval for most fluids. Rather than guess, we check level and condition at every visit, so you know exactly what is due next and what can wait. Bring it to our shop in Martinez, Augusta, Thomson, Aiken or Warrenville and we will lay it all out on your phone.