Recently I have worked on a number of pianos in which it has been several years since they were last tuned, with some being greater than half a step flat. If you are worried about your own instrument because it has been many years since it was last tuned, don't be.
No matter how out-of-tune your piano may be, I can assure you that it can be tuned and the pitch raised to where it is supposed to be, as long as there are no major structural problems.
Daytime, evening and weekend piano tuning appointments are available. Call 618-654-1585 or send an email with your request and contact information to: srensberry@rensberrypiano.com -- Steve Rensberry