Brake fluid changes should be done every 2 years usually.

Engine flushes are not something I do or recommend but, there are others who will say it is necessary.

Some years ago I was offered, as extras for the service, both a brake fluid change and an engine flush. This was by my local Ford Main Dealer.

I agreed to the brake fluid change but refused the engine flush. I'd read plenty of articles in motoring magazines, which I used to subscribe to, saying this probably wasn't a very good idea. Also, it certainly isn't recommended by Ford.

I think they'd just recently had a company rep in to see them. The cans of engine flush and accompanying posters were absolutely everywhere in the service reception. From what I remember it wasn't a Ford product, either.

Most manuals will state not to use oil and fuel additives as they can damage cats and other emmision system components. But this has never stopped garages selling the stuff.

Brake fluid changes are a sensible precaution but some makes use 2 and some 3 years changes. Our Ford dealer used to check for moisture with a sensor or something and only recommend a change when the boiling point dropped below their figure but I still had it done every 3 years since the moisure can cause corrosion inside brake components.