&gt; and I was amazed that something could possibly fly that long<p>It isn&#x27;t the same plane flying 30 years later.  There are standardised checks done at various intervals, including the D check which takes the entire plane apart.  <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Aircraft_maintenance_checks" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Aircraft_maintenance_checks</a><p>Those checks will replace damaged and limited life parts.  The cabin fittings have to be taken out for the D check anyway, so many airlines will replace them at that point if not sooner (eg carpets wear out a lot quicker).