The ones that fool people for more than a week aren't the ones that look perfect under the shop lights. They're the ones with a bent stem, an uneven bloom, a leaf that's slightly the wrong shade of green, because that's what real flowers actually look like. I learned that the hard way with a vase of peonies so symmetrical and so uniformly pink that a guest once asked, straight faced, if I'd had them laminated.
Good fabric or foam stems hold their color for years if you keep them out of direct sun, which fades the cheap dye jobs fast and leaves the good ones mostly fine, maybe a shade softer by year three. Dust is the real enemy, not time, so a quick pass with a hair dryer on cool or a soft brush every month or so keeps them looking like something you chose rather than something you forgot about. The day they arrive, check the stems before anything else: real wire wrapped in floral tape bends and holds its shape, while the hollow plastic kind snaps at the first attempt to angle it toward a window, and you will want to angle it, because a stem that only works pointing straight up looks like it came out of a box, which it did. Run a finger over the petal edges too. The better ones have a slight texture and a slight irregularity in the cut, which is the whole trick, and the bad ones have that telltale plasticky sheen and a seam you can feel if you're paying attention. Smell them as well, which sounds strange until you've unpacked a bunch that reeks of warehouse glue for a solid week. These suit the rooms that get hard light and no water nearby, a bathroom with no window, a stairwell landing, a kitchen table in a house with a cat who considers anything in a vase a personal challenge. They're also the only sensible option in a rental where you're not about to commit to cut flowers you'll forget to change out before a showing. If you're starting with nothing, go for a single stem type you actually like in real life, something architectural like branches or a few large magnolia style blooms, rather than a dense mixed bunch, because one good stem in a plain vase reads as a choice and a cheap mixed bunch reads as a prop.
A good fake flower should make you suspicious before it makes you comfortable, and the bad ones never even get the chance to do either.