Yes, in my experience it is. You are buying a unit and technically own only the interior space, but the systems attached and the external are also a part of what you are buying into. If the plumbing or siding have defects, you may end up with an expensive special assessment to address the issues in the near future.
If there are 100 units in the complex, you own your unit and 1% of the rest of the complex. I sold a unit a year ago with bad siding and a broken pool. We found out that they were in the midst of getting bids and preparing to address the issues. My buyer knew going in that this would be coming down the road. We renegotiated our offer and she bought it now, fully informed.