Brake fluid

My mechanic recently told me that I need to change my brake fluid every 30k. Is this excessive?

Every 3 years regardless of mileage is probably ok.

Every 2 years would be better.

Nope! If the Jeep has ABS, take care of the brake fluid and it takes care of the ABS and the other brake components. It’s far cheaper to maintian the fluid than to replace a component in the system.

The same holds true with all the other systems that use fluid. The power steering, transmission, differentails, transfer case, cooling system, take care of these fluids, and the components last longer.

Tester

I change brake fluid every 3 years, and I drive only ~10K miles over that period.

No it is not excessive.
It is necessary if you want to keep your brake system–including the ABS mechanism–functioning well enough to be able to stop the car.