It depends on a few factors.

1. The location of tattoo, some regions of skin are VERY sensitive.

2. The skill of the tattooer. How deep do they go, how fast do they pull, etc...

3. The size of the lines and shading A fine line tattoo feels very different that a block shaded piece. (One needle vs up to 7)

4. The style of the tattoo. Black and gray realism tattoos require the artist to go over an area many times. Going over an already inflamed piece of skin feels way worse than fresh skin.