I would be willing to make a VERY LARGE bet that your 75 Pontiac, or whatever it was, has not gone almost 30 years with no brake hydraulic attention.

My MB's, with annual brake flushes on the other hand, have never had any hydraulic attention and still work fine.

As stated earlier in this thread I'm sure, brake fluid absorbs moisture, moisture makes corrosion. Regardless of what you drive you have two choices. Flush brakes annually, using $2.00 or less worth of brake fluid, or periodically do expensive brake hydraulic repairs. Your choice.

Have a great day,