Time being the perception of change (as from Julian Barbour's End of Time) is what it all comes down to when you think of it. Movement of objects around you (arms of the clock or planets/stars in the sky) or changes in forces and fields (digital clocks affected by the alternating flow of electrons, body chemistry affecting your internal housekeeping) But I don't have the brains though to come up with a means of how all these instances of changes come together. The only Planck-time experience I have is when I hit my head on one.
