Why do clock and watch dials use a quadruple "I" as the Roman numeral for 4?

This is for Matthew Alice:

Why do clock and watch dials always use a quadruple "I" as the Roman numeral for 4, but everywhere else the Roman numeral for 4 is "IV"?

-- Befuddled Bob, telephonically

Call it tradition, call it lack of imagination -- but that's the way we've always done it. Since way before Timex but a few thousand years after the Egyptian stick-in-the-ground clocks. When Romans adopted Egypt's sundial, they marked the hours with their cumbersome, goofy numerals. The number 4 in the original Roman system was IIII. The Romans' early numbering technique was all additive; 444 had to be written CCCCXXXXIIII (400+40+4). It was undoubtedly some overworked stone carver who came up with the subtractive system, in which 444 could be written CDXLIV ([500-100]+[50-10]+[5-1]), 6 characters instead of 12. Sundial makers and later clock and watch makers never changed the old IIII. Actually, more curious than the IIII is the fact that 9 on watches is written in the new Roman subtractive system, IX. Perhaps VIIII wouldn't fit neatly on a small clock or watch face. Probably won't make much difference in a generation or so, when digital is the law. How many kids today can read a dial clock anyway, let alone a clock with Roman numerals?