Brake Fluid

Surfing thru the EngineBible website, I just found out that brake fluids (DOTs 3 and 4) are not petroleum products but closely associated with ethylene glycol, same stuff used in anti-freeze. DOT 5 on the other hand is silicone based fluid and is not recommended for use in vehicles with ABS. DOT 3 & 4 fluids have the affinity to absorb water. The report said that after about two years, a typical brake system could contain about 3% water resulting in lower boiling point. It was recommended that every couple of years to have the brake system purged and fresh brake fluid installed. Further suggested also not to store previously opened brake fluid containers in one's garage overtime because the fluid absorbs moisture. Anyone have any comments on this?

Yep heard that before. Never changed the brake fluid on my car, main reason being is that you can't see it like you can on a bike, thru the sightglass. Not a good reason but outa sight, outa mind I guess.
Bike, I do the brake/clutch fluids every other year.....usualy :-)....Mike