A good piano has an average life-span of 60 years (100 years for the prestigious makes). A cheap piano will be derelict after a few years... and will inevitably need costly repairs. A good-quality instrument may therefore be considered as a sound investment.
Unlike some other instruments, pianos do not gain in value with age. Value guides are not available, and age alone is not enough to estimate an instrument.
Repairs will not transform a piano into a new instrument. However, regular maintenance and a stable home environment will help you get the best of your instrument for a long time. A well-kept instrument will also fetch a better price on the second-hand market.
As usual, buying the cheapest does not mean cutting costs. A high discount will usually mean that you will get poor service or no service at all on an instrument which may not be as new as it looks.
Fortunately, there are many good makes on the market. Trust an established name, a name that will still be around in a few years' time! This is especially important if you decide to sell the instrument.
Some dealers will tell you that the piano they are offering has a metal frame. All pianos are built with a metal frame to ensure optimal tuning stability. But this is not a guarantee of quality. Also, the quality of the cabinet's wood has no influence whatsoever on the sound. Only the soundboard wood quality is important.
Belgian pianos no longer exist. A few dealers assemble parts purchased in Asia and offer a "Made in Belgium" label which should read "Made in Corea".
On the long term, it is advisable to go for a good piano and avoid the expense of changing instruments on the way.