Regulation is the adjustment of the piano’s action to ensure a smooth and even touch throughout the keyboard.
How often does a piano need to be regulated?
For most pianos, once every 5 – 10 years should be adequate.
What would cause my piano to go out of regulation?
Your piano would have been regulated at the factory where it was built. Fine quality instruments obviously receive more attention than models on the low end of the price spectrum, but even the most expensive piano will go out of regulation over time.