Here's a question we get more than almost any other, usually whispered like it's a little embarrassing: will these turn yellow?
It's a fair thing to ask. If you're spending real money on a set you want to keep for years, you deserve a straight answer instead of a marketing one. So here it is.
Cheap acrylic can yellow over time, mostly from two things: constant direct sunlight and heat. UV light slowly breaks down low-grade plastic, and a set left baking on a sunny windowsill or in a hot car will age faster than one that isn't. That's true of a lot of acrylic products, not just mahjong tiles. The good news is that it's almost entirely preventable, and none of the prevention is difficult.
Keep them out of direct, all-day sun. A game room that gets afternoon light is fine. A set displayed on a windowsill that gets six hours of July sun, every day, for years, is asking more of the plastic than it should. If you display your set (and our tiles are printed to be displayed), pick a shelf that gets bright room light rather than a sunbeam.
Don't let them cook. The trunk of a car in summer is the single worst place to store tiles. Heat is what warps and dulls plastic. Room temperature is all they want.
Clean them gently, and dry them fully. Wipe tiles with a soft, damp cloth: water, or water with a tiny drop of dish soap. Skip alcohol, acetone, nail-polish remover, and abrasive "magic" sponges; those attack the printed surface and can haze the acrylic. Dry each tile before it goes back in the case, because trapped moisture is what causes that musty smell in old game boxes.
Store them closed, away from ink. A case with a lid keeps dust off and keeps the color from meeting anything that might transfer onto it: newspaper, a felt-tip marker rolling around a drawer, that kind of thing. Our sets come in a zip case with a clear lid for exactly this reason: closed and protected, but still on display.
Do those four things and a good acrylic set will look the same in year five as it did on day one. We build ours with UV-printed color sealed into the tile rather than painted on top, specifically so a lifetime of shuffling doesn't wear the design away. The surface you shuffle isn't the surface the design sits on.
One last honest note: a little personality is normal. Tiles that get played develop the faintest smoothness on the edges, the way a good deck of cards softens with use. That's not damage. That's a set that's actually been enjoyed, which, when you think about it, is the whole point.