We recommend a Power Steering flush to protect the pump from premature failure because of contamination when the fluid has started to deteriorate.
Driving your car for extended periods without power steering fluid can damage the pump. While there's nothing that physically stops you from driving your car if you have a power steering fluid leak, once the level drops, your pump runs dry. This causes increased friction and heat and can quickly cause expensive damage.
A whining or squealing noise when the wheels turn can be an indication that the power steering fluid is low.