A lot of technicians/tattooists will see a client for one appointment and expect the treatment to be complete.
The way I work is, I like to see my clients for their first treatment appointment, where I drawer on the template, choose the pigment to suit the client #blondes #brunettes - I always involve my clients when drawing on the template, this way my client can advise if they would like to go thinner, thicker, longer, shorter, once my client is happy the procedure can begin. Now its extremely difficult to foresee how a treatment will 'pull' over the following 4 weeks after a treatment, which is why it is nice for the client (and me) to see the client once again to go over, adjust and check on the treatment to make sure both parties are happy. Sometimes, clients like to start off on the thinner side/lighter colour, then the second appointment they feel they can build on this and go darker/thicker, or quite happily just stay the same shape and shade as before. I always advise my clients to leave the appointments at least 4 WEEKS apart, this is to allow the skin cell renewal process to complete itself.