My personal opinion on this topic (being a girl with both tattoos and piercings) is that it is a personal choice. I feel though on a personal level that tattoos although they are of course, permanent, are a constant reminder of the person you are and what you like. Of course when you reach your 50s/60s they are not going to look as good as they did when you were in your 20s but they remind us of the life we have lived and sometimes the things we have achieved or the people we have met. My tattoos will remind me of who I am and who I was as a young girl when I am older. I feel that you only live once and our bodies are just a means of transporting our souls to the next 'life' if you like. I don't see it as mutilation but art!
I think they can look good but a lot of the time, they can also look awful on some people. I'm not a fan of a lot of facial piercings, i find them quite off putting.