At our weekly staff meetings (now monthly since our move to the new office) we would often have someone talking about their work with Wycliffe, usually in some distant country. Often people carry on into their 60s and 70s before they stop. These older people (older than me anyway) would have great stories to tell, and there would obviously be so much more they could say, given the number of years they have been doing the work. Apart from their usual wrinkles I would wonder why their exploits left no obvious physical trace. There was no sign of the days waiting in line to get visa or travel permits, or some other government documents approved, the days and weeks they'd spent travelling along muddy tracks in their 4x4s, the months and years they'd spent patiently working through a translation with speakers of the language.
It put me in mind of Maori tattoos which I thought (until I researched for this post) were about what had happened to you, but I now know are about your social standing by birthright and also about "the quality of their personal participation" (see that linked webpage). You could imagine a translator getting a tattoo after they worked on a New Testament, or Old Testament - maybe one dot or line per verse (7,959 in the New, 23,214 in the Old), or more realistically per chapter (1,189 in the whole Bible). It's not uncommon that when someone has finished on such a project that they then move onto being a consultant for other projects in the same area of the world. So they might be involved in several more projects in their remaining working years. So the first tattoo would need to not be too big!