I had a client tell me a story about one of her friends, and how he had lost his daughter. I told her to get him down to my shop, and upon arrival I let him know that I wanted to do a tattoo for him, and I wouldn't charge him. He returned a month later with a disc full of pictures of her and told me that I could pick the one I liked best. I picked one, and it happened to be his favorite. I spent almost six months studying her face, and we ended up doing the tattoo a week before her one-year vigil. This tattoo is probably my favorite tattoo I've ever done.
Many times when people think of getting tattooed, they think they focus on the pain, and it deters them from getting a decent tattoo. Many people will say, "Go big or go home!" And the reason is, because no one ever says, "I wish I got it smaller." In ten years of tattooing, I've never heard a single person ever complain their tattoo was too big, but I have heard hundreds of times, they wish they had gotten it bigger. By getting medium, or preferably larger tattoos, the artist can add more texture, highlights, and contrast.
Cover-ups can be an extensive process. Me personally, I don't like to approach an older tattoo by trying to cover it up in one pass with a new tattoo. I always approach it with the mindset that it may take three to four sessions to make the old tattoo disappear. This process involves doing the new tattoo, while lightening the old one. It takes time, but the result is much nicer.