More is almost always better, whether we're talking about cake or trouser knees. Fortunately these pants aren't made from cake (or is that unfortunately?) but they do have a double-knee construction.
What it means is you can treat them twice as rough and they'll handle it. Given how durable Gramicci's single-knee'd pants have proven these are likely to last a while. The velcro tabs at the base of the knee panels also means you can chuck a couple of kneepads in there and add some protection when you're out there dangling from a rock.