Just like us, a plant’s appearance can change depending on factors such as sunlight and stress. Unlike us, plants tend to get far more attractive when stressed. If you notice your plant looking a little different than before, or if you recently ordered plants and they looks slightly different than the photo(s), it can most likely be attributed to stress and/or sunlight.
Stress
Succulents experience stress for a number of reasons, including infrequent or conservative waterings, exposure to colder-than-normal temperatures, shipping, repotting, etc.
When your succulent is slightly water deprived or has recently been exposed to cool weather, it will typically bring out the brightest and most vibrant colors on your plant. For example, if you leave a pink echeveria outside on a 50°F day, that same echeveria will be a much brighter pink than it would be on an 80°F day. The same pink echeveria would have a similar reaction to doubling the amount of time between waterings.
Sunlight
In order for your succulent to maintain the correct color, it needs to receive the correct amount of sun exposure. If your plant isn’t receiving enough sun, its color will generally be duller than normal. On the other hand, when a succulent receives slightly more sun exposure, this can bring out the deeper, richer tones of the plant. If your plant begins receiving too much light, you’ll be able to see what looks like bleaching of the leaves or even sun spots. If you notice your plants look like they’re receiving too much light, move them to a location with less direct sunlight.
In both scenarios, the color(s) of the plant can revert back to their original lightness, so the visible changes are not necessarily permanent.