All LED Strips, no matter how great their quality, are subject to degrading over time. This is perfectly normal, although we can take measures to ensure that the degradation process is slowed down, so that the strips can function well beyond their warranty period.
In many instances, LED Strips can start to exhibit discolouring if they've been exposed to certain elements such as smoke, water, humidity and hot air. Installing an LED Strip on a non-conductive surface like wood, brick or plastic can introduce problems later on, with few exceptions, such as a cement wall, being ideal. Generally speaking, it is "acceptable" to install 4.8W/m and up to a 14.4 W/m LED Strip on these kinds of surfaces, but exceeding this with High Density products in our 3528 or 2835 range will inevitably impede its ability to function properly.
In most instances, it's safer that we suggest the customer places their strips within a profile to help regulate airflow and better disperse the heat. Failing that, metals such as aluminium and stainless steel would provide excellent surfaces, and in some cases can be comfortably installed within the home, if using something like an Aluminium flat bar, which can be purchased inexpensively.
We strongly discourage that you purchase cheap LED Strips, as we've found that their silicone layers can begin to discolour with an ugly yellow hue after just weeks of being installed and that the diodes simply burn out.
Take care of your lights and they'll serve you well in the many years to come.