Tattoo Touch-Up Timing Calculator

Touch-Up Interval is set entirely by the four selection inputs -- Ink Type, Sun Exposure, Placement Exposure, and Skin Tone -- multiplied together and rounded to one decimal place (line 25). Years Since Tattoo is never referenced anywhere in that calculation; it is only used afterward to compare against the interval that has already been computed, so it cannot move Touch-Up Interval no matter how large or small it is.

Touch-Up Interval starts from a base of 7 years for traditional ink, 4 years for organic or vegan ink, and 2 years for UV or glow ink (lines 11-14), then that base is scaled by Sun Exposure and Placement Exposure factors that only ever hold it steady or reduce it, plus a Skin Tone factor that reduces it 10% for fair skin but raises it 5% for dark skin, since the calculator models fair skin as showing fading more noticeably (line 23).

Estimated Fading is calculated as Years Since Tattoo divided by Touch-Up Interval, converted to a percentage and rounded, then explicitly capped so it can never report more than full fading (line 29). Because Status and Touch-Up Cost both key off this same capped value, a tattoo many years past its interval reports identically to one that just reached it -- both show 100% fading and the "Overdue for touch-up" status.

Touch-Up Cost is not read from a continuous formula -- it checks a single condition on Estimated Fading: 75% of original cost once fading reaches 75% or higher, and 50% of original cost below that (line 37). Two tattoos with very different fading levels, such as 20% and 74%, report the identical 50% touch-up cost, while crossing the 75% fading line jumps the estimate straight to 75% with no value in between.