Depends on the placement, size, details, pain tolerance, skin type, exc.
For a general presentation:
Small tattoos up to 15cmx15cm (half or 1 session)
Half sleeve (2-3 sessions)
Full sleeve (4-6 sessions)
Chest (1-4 sessions)
Half leg (2-4 sessions)
Full leg (4-8 sessions)
Full back (5-8 sessions)