I sailed on the Caribbean Princess after I sailed on the Emerald. The Emerald was only 6 or 7 months old when I sailed her and was, of course, in perfect condition. The Caribbean was before she went into be refurbished, and even though there were a couple of areas showing wear and tear, she was spotless. If you've ever sailed on Princess, you will know what I mean. They are ALWAYS painting, replacing carpet, replacing mattresses, replacing chairs, etc. Of course, most lines do. And they are ALWAYS cleaning. So, even if the fabric might be faded, it's going to be clean. I don't know who said the Emerald was showing her age, she's only a couple of years old. Not sure what they were referring to, faded upholstery?, worn carpet?, light bulbs needing to be replaced?, someone spilled something?
I have spoken with various crew members and they have all told me the same thing. They replace items on board, constantly. There are some things that they have to do in dry dock, but most everything is done while sailing or in port.