Okay! You are planning to do a tattoo on your sleeve only if you can see it how it will look after 20 years. But, who knows what will happen to the tattoo after 20 years. If you take the right steps as suggested by the tattoo artist, the tattoo will look new even after 20 years. But, if you do not take care of the tattoo and do it from an inexperienced tattoo artist, you will lose the colour just after few months. So, if you want to keep your tattoo new, even after many years, you must follow the guidelines as given by the artist, and do the tattoo from a trusted tattoo shop.