Buying a used music instrument have advantages since you can find a good quality instrument at a lower price that buying a new one, and the only disadvantage that you do not have guarantees.
We must consider these 3 points:
- Who and Where: A good factor would be to know to who belonged previously and if you are buying it of he himself owner you can consult so that it sells it, the use, etc.
If you're buying it from a music store, you can consult the salesperson if it's possible to know the name of its' previous owner, how long it's been in the store, etc.
- Overall Condition: It's recommendable to go with some person who knows musical instruments to accompany you at the time of buying an instrument.
They can help assess whether the instrument is in good condition by listening & playing it.
- Value for your Money: You must consider that the money that these paying for the used instrument is worth it, for it you must know the price of a new and compare it.