Worksheet_Change is a worksheet event and must be in the sheet module not a standard module.
It will re-write I2:I30 every time A1 changes, not hourly.
And that is actually dependent on how A1 receives its value.
If there's a formula in A1, the Worksheet_Change event will never trigger, because what's in the cell (ie: the formula) never changes even though the displayed result does.