So long as the furniture is made from good quality wood from the start quite often that piece you think is too far gone is restorable. Here's an example of an oak coffee table that was left on the back porch in the weather for a decade or so. I knew as soon as I layed eyes on it it had great potential and it sure did. It did take some work but it was well worth it.
Sometimes you might have a piece that isn't that precious but because of it's original quality might be easily transformed into something new you can appreciate and use everyday. This piece was an old bed frame found in a barn. The customer originally asked me to make it into an out door sit space/love seat but when she came to pick it up she decided her dog would like it even more so it became a dog bed! She's working on a custom sewn pad for it. The original piece was clear, old growth fir and red pine so it was well worth preserving for any use.