Well, someone told me the other day that reusing them like this was just sad and cheap and that I should do all new arrangements each time. Apparently, I'm dishonoring my parents by reusing the same flowers. (Never mind that at some point, they're not only going to be reused, but they're going to sit there unchanged until the mausoleum caves in because they'll never look terrible and I doubt the cemetery will ever remove them.) I've kind of felt a little off about it myself, but at the same time, I can't stand waste and my parents abhorred it, too (depression-era babies), so I've just continued to do it. I can't imagine they'd want me tossing perfectly good flowers in the garbage.
But am I really being terrible? I'm not a religious person, so I don't believe they're "up there" taking inventory. I could just have the vase removed, and I probably will one day in the future just to keep the aforementioned "endless flower" scenario from happening when I die. But for now, she wanted it so I'm trying to honor that request.