We have furniture from IKEA that we bought at least five years ago that still functions great. A mattress we got from them is absolutely stellar with a memory foam topper; all of our guests love it. I think our coffee table is ten years old now.
However, everything goes to hell once you try to take it apart. This is why our mattresses are not on IKEA bed frames. Taking them apart has ALWAYS weakened them significantly. (We use Thuma Japanese joinery bed frames, which are AMAZING for moving and very high quality).
Which is kind of moot when you're talking about high-quality furniture, as they are usually single pieces as well.