I recently had an interview with a member of the Garda force, Seamus. He has two tattoos, one on his shoulder and one on his upper arm. While both cannot be seen during his work, he tells me that a workmate of his needs to constantly wear long sleeves in order to cover up an ornate 'D' on his forearm.
Seamus's tattoos were done when he was younger, for a few different reasons. The spider one was not completed to a high quality the first time so he got it re-inked in recent years to bring it up to a better standard. The main reason behind these tattoos Seamus tells me, was to remind himself of the person he used to be and to not allow him to return to that place.

But regardless of the fact that he had to get one re-done, he would not change them at all. "they're a part of who I am now, they were done when I was in a lower place and they'll always remind me to look up and reach ahead."