All hardwood floors will gradually discolor over time, as the stain and wood is susceptible to ultraviolet light and frequent use, but you can minimize these effects with some simple steps.
Squash bugs are a serious problem in the Western Hemisphere and can be found from coast to coast in the U.S. They suck the vital juices from plants and can inject a toxin that causes otherwise healthy plants to wilt, discolor and die.
If you place one in an area that's exposed to high humidity, it will resist oxidation, and if it's located in a kitchen or smoking room, it won't discolor and can easily be cleaned with vinegar or a damp cloth.
However, tetracycline is usually not prescribed for children until after all of their permanent teeth have erupted, as it can permanently discolor teeth that are still forming.
The downside to tiles with decals is that the decal may eventually degrade - either discolor, bubble, crack or peel - due to cleaning, water and the heat of the kitchen.