All pianos need to be tuned at least once a year but preferably every six months, even if the piano is not being played regularly. Because of the way pianos are made they are affected by changes in temperature and humidity as well as just by being played. All these will affect the tuning over time.I aim to tune all pianos to concert pitch which is A440hz. However some pianos are not able to reach concert pitch because of their age or condition. In those cases I will usually be able to tune the piano to itself or gradually raise the pitch over a few tunings.
Whether it is an old family heirloom, something for the kids to learn on or a Concert Grand Piano, I will be happy to advise you on the best way forward for your piano.