Pianos although made to last for 60 to seventy years often survive for much longer.
However, in order for them to be in top condition they should be serviced regularly.
A piano is normally made of wood and steel and both of these items expand and
contract under certain conditions.
The strings are attached to the frame and are held under enormous tensions.
The piano is a percussion instrument and every time a key is hit the stings
vibrate and can cause very small movements.
The tuning pins are held in by friction alone as each pin although threaded
it is not like a wood screw and can work loose.
A piano is subject to changes in both temperature and humidity and I would
recommend monitoring this regularly otherwise your new pride and joy might
be permanently damaged.
Recommended temperature is between 18 - 21 degrees C (65-70 degrees F)
Recommended humidity between 45 - 60 %