All tattoos fade over time and over sun exposure. The best you can do it make sure to moisturize the area daily and listen to the instructions from the parlor about the first weeks care after you get it. If it fades, you go to get it retouched. The more you take care of it, the less likely it will need to be retouched within the next 15 years give or take. White tends to fade the quickest.
They fade the quickest but they also have a tendency to have the ink become runny on the skin. They are still perfecting this particular process, as they are with the various eye and mouth tattoos, so I would ask a professional in that particular feild of art. Regular tattooing has existed for thousands of years beginning in asia. It's for the most part, already perfected.