While adult skin has reached its maximum size, it can still expand as a result of weight growth, loss, and muscle increase/loss. Any change to the skin has various consequences. When tattoos are put over a muscle, the tattoo may stretch if the muscle mass in that location is later increased, or simply by growing. If a person loses weight, then the skin will shrink and any tattoo done at full size will look smaller later on. Finally, if a person gets a new tattoo, the old one will fade away. The skin's ability to grow depends on how you grew up and what kind of lifestyle you have had. For example, someone who spends a lot of time in the sun can develop melanomas, which are cancers of the skin, so keeping tanning beds and sun lamps out of reach of children is very important. Someone who works with their hands can develop calluses on their palms from using metal tools, so it is recommended to get tattoo removal treatments every six months or so for these tattoos. Tattoos can also become problematic later in life when the skin starts to thin or age. The ink under the skin can be seen by some people, especially if they are going through chemotherapy, and this can be distressing for those fighting cancer. However, most people will not see the tattoo until they have an issue such as a cut or bruise and need to know where to look.