As you age, so does your tattoo.
The undeniable fact is that tiny details, light color and light shades of grey will not hold up over time. The ink will fade and spread, Light colors and light shading will be first to fade away leaving you with only the darkest most solid bold details. Small details will spread and grow together until you can no longer make out what you are looking at. A well built tattoo will be planned to compensate for this.
This brings us to some of the other styles of tattooing that are built to last. They have solid lines, solid shading and lots of space to spread out. Japanese style tattooing in particular has been developed over many generations to work with the challenges of an aging tattoo. Whenever possible I try to employ the principles of the Japanese style while designing any tattoo.