IT DEPENDS
You can get a variety of answers on this depending on who you talk to. If you go to a music store that does not have a rebuilding shop, you may be told that buying new piano is better than fixing an old piano. If you talk to a rebuilder that does not sell new pianos, you may hear just the opposite.
The truth is somewhere in the middle, and can depend on your specific situation, and how you view life. Some people appreciate the quality and history of older instruments, while others may feel that a new instrument will last longer.
In reality, if an older instrument of good quality is maintained (or rebuilt to original or better specs), then they can easily last another lifetime, with little or no more expense than a new piano.
Some new pianos today are not built with the same quality of components as those from 50 -100 years ago. In the end, it may come down to what you like in the sound and appearance of the piano you choose. Just don’t be afraid to consider repairing or rebuilding an older instrument.
Your piano technician can help you decide the best course of action.