Hi Julia,
We farf about with just the one set of piers and ONLY take out the relevent numbers required, so none get lost in the tattooing, make sure to test on a piece of paper for the tatoo numbers to be the right way round, our pliers are over 40 years old and still work a treat. No doubt Robert will know exactly how old they are when he read's this post and will confirm their age.
HTH
Lillian