Honda Break Fluid
 

My Honda Civic 2002 owner's manual states that the break fluid MUST be
replaced every 3 years. Furthermore, it states that ONLY Dot 3 Heavy
Duty Honda break fluid must be used. The manual states that the use of
other break fluids apart from Honda's will result in system corrosion.
My mechanic tells me that I should not bother about only using Honda
break fluid, and that he is using Dot 4 in his shop. He says that what
the owner's manual says about only using Honda break fluid is nonsense.
Should I believe him and use his Dot 4 fluid?