Real numbers, from pieces that are finished, not optimistic ones.
A full day with Federico is roughly six to eight hours of actual tattooing with breaks, not a two hour appointment. Every number below is counted in those days, so you can compare them to what another artist quotes you.
The limit is not the artist's stamina, it is your skin. A worked area swells, and ink does not sit predictably in swollen skin. Past a certain number of hours you are no longer improving the tattoo, you are just trading tomorrow's quality for today's convenience.
Between sessions the skin needs weeks, not days. That is why a back piece is measured in months even though the actual work is a week of hours.
If you are flying to a convention stop, scope the piece to what a day or two can genuinely finish, or accept that you are starting something and continuing it at the next stop. Both are fine. Pretending a sleeve fits in a weekend is not.
Multiple full days spread across months. The exact number depends on how dense the design is and how your skin takes it.
Seven to eight full sessions is what his finished backs have taken, spread over months.
Sometimes, on different areas. On the same area, the second day works on skin that is already swollen, which costs you quality.
Usually a few weeks, enough for the area to be fully settled. Rushing it is the most common way people damage their own tattoo.
Requests go straight to Federico, not to an agency inbox. He answers from his own address.