Supposedly every 5 years or 30K miles , I’ve had that done that only once during the 115,000 miles I’ve put on the car so far , but don’t remember at what mileage, or the year ..
If you’re concerned about the effectiveness of the anti-freeze / coolant , you can buy a tester ; they’re cheap and can be found at most auto parts stores , or online . I have one buried somewhere in the garage but haven’t used it for ages.. I only use the brake fluid tester every couple of years to make sure moisture hasn’t accumulated there ( it does whether you drive the car or not ) . That fluid “ should be “ changed every two years , but I usually go by the tester indication... I’d do the same with the coolant flush .
