A well tuned piano can inspire.
A regular tuning takes about 2 hours. There are 220 individuals strings in most pianos and more in large, concert instruments.
There are many factors affecting the tuning such as make, model, age, humidity and temperature changes.
Regular tunings every 6 months is highly recommended to keep the piano in good condition and maintain tonal quality.
Simple adjustments are included with a regular tuning. Other repairs are available.
General supplies are included with the price.
See the following for piano care from Steinway.com.
Here are some interesting links:
Quiz On The Piano
Bluebook of Pianos
The Piano Resource Directory