Have your piano tuned every year. Due to the tremendous amount of tension on the strings, pianos are constantly needing service. A piano will be out of tune after six months, but after a year it may be drifting significantly flat. Therefore, tuning once a year is considered the minimum. However, pianos that are tuned every six months stay in tune better and thus retain their value longer. Pianos go out of tune even when they are not being played.
Note: brand-new pianos, because of the elasticity of their new strings, drift flat much faster than older, more stable pianos. This is why the manufacturers usually recommend four tunings in the first year of a new piano’s life in its new home. From there you can begin the normal schedule of tuning once or twice a year.
Play your piano. The mechanical parts inside your piano need to be regularly manipulated in order to keep everything moving smoothly.
Have a humidity-control system installed (if you don’t have one already). South Florida is extremely humid year-round. The variations in humidity can have unpredictable effects on the piano so it’s best to get it under control. Many pianos are sold with humidity-control systems installed already. To see if you have one you can look behind the knee-panel (in a vertical piano) or underneath (in a grand piano) or just look for a power cable hanging out.
In the long term: After about 10 years the mechanical parts inside the action will be wearing down and need to be either adjusted or replaced. Your technician will handle little things as they break down during your regular tuning visits, but after a long time so many things will need attention you will need more significant repairs or a more thorough process called regulation to make everything feel ‘regular’ again.
In that same amount of time, the hammers will be so compacted from being played that the piano may begin to sound ‘pingy’ or ‘bright’ or ‘like broken glass’ as it has been described. You can check this yourself if you look at the hammers inside the piano. Worn-out hammers will have deep grooves where the strings impact them and they will be flat in the front instead of round. A process called voicing can soften the bright, harsh tone caused by worn-out hammers.
Tune your piano after you move it. The simple act of lifting, setting down and rolling disrupts the careful placement of its ~236 tuning pins, and humidity and temperature variations in its new environment will cause it to go out of tune. Schedule your tuning for three or more days after you move to allow it to acclimate to its new home.
In fact, just moving the piano to different areas within your home can cause it to slightly lose its tuning, especially if it is to or away from a window that gets direct sun, a sliding glass door to the outside, an air-conditioning vent or any other area that experiences hot and cold shifts throughout the day.
If you are a recording musician, it is absolutely essential to have the instrument tuned to A440 directly before a recording.