power steering and clutch fluid: almost never need to change.
juz top up periodically.
brake fluid: differing opinions, but generally, the harder u work
ur brakes, the sooner u have to start replacing them. like engine
oil, brake fluids are subjected to temperature changes. the more
often u brake hard for long durations, u increase the chemical
deteriotion of the fluid. beyond this, the brake fluid boils and
leaves "air pockets", reducing pedal feel and increasing braking
difficulty. recommend changing new fluid every 30k under normal
driving condition.
coolant: normal water contains chemicals, which will corrode the
interior of ur radiator and form deposits within water channels of
the engine. distilled water comes 2nd best compared to modern day
coolants. u better think twice bout visiting the same mechanic who
told u normal water is okay. next time tell him put green tea
better. 
