Used Buying Piano Checklist
Quick reference to find the age is knowing make, model and serial number. By those pieces of information, you can find where the piano was made and the year it was made.
When purchasing a used piano there is going to be some red lights to look at:
Looking at them, look to see if there is proper spacing between all, make sure none are lower than others (keys depressed)- could be a small problem, could be a big problem.
With an upright- lift the lid. With a grand, look inside the "belly"
make sure they are all the same length and evenly spaced. Sometimes pins become loose, they will pound them in making them different lengths, with that the tuning pin block will become loose and become untune able- at the point of requiring a treatment- Pin tightening treatment. Or pin block restorer.
You want the hammers to be pretty soft. Really hard and grooved hammers make for hard playing. There is options of sanding them down to get a little more life- but typically with hard and grooved hammers they will need to be replaced.
Should be shinny and bass strings should be thicker- coil looking. Rusty strings are not a great sign. Strings break with age, wear, and humidity.
check for cracks- cracks happen with too much humidity and hot temperatures. They will make buzzing sounds.
There are so many other bits and pieces inside the piano that can break, some wood, some plastic, and felt. All replaceable but at a cost.
Pedals: Make sure all of the pedals work- there functions are for:
Right/ Sustain: Lifts every damper in the piano off the keys "letting the notes be held and keep vibrating"
Left/ Soft: shifts the action to play one or two notes instead of 3
Middle/ Sostento: sustain only certain notes (one that was pressed down when pedal was pushed)
**on Uprights: actions isn't actually shifted- but rather the pedal often called the "half blow pedal" hammers are moved closer to strings- creating softer sound