Conditions
As you might expect, it is probable that any piano kept in regularly fluctuating conditions will be suffering from a combination of the above problems, typically: (a) Rust on strings/strings break on tuning; (b) Notes sticking due to overly-tight centre-pins in flanges, (c) Loose tuning pins causing tuning instability (d) Splits in bridges around the bridge-pin areas.
Alas and alack, all of the above problems are to be found in many pianos here in the UK, along with the related issues of woodworm and moth (see below).