Sub blah()
'Do a one-time calculation of what 10 minutes is in decimal days and round it to 5 decimal places (it saves recalculating it 2*144 times; because it gets used 2x in the loop):
interval = Round(TimeValue("00:10:00"), 5)
'take each cell in the range A1:A14, one at a time (cll is that cell):
For Each cll In Range("A1:A144").Cells
If interval <> Round(cll.Offset(1) - cll.Value, 5) Then 'take the value of the cell below cll (cll.offset(1)) and take away the value in cll itself, and round the result to 5 decimal places. If that's not equal to the rounded 10 minutes (interval) then do something:
cll.Offset(1, 2).Value = Round((cll.Offset(1) - cll.Value) / interval, 0) - 1 & " missing value(s)?" ' put something in the cell 1 cell below and 2 cells to the right of cll (cll.offset(1,2)). That 'something' is:
'the difference between cll and the cell below it ((cll.Offset(1) - cll.Value)) , divided by 10 minutes (interval), then rounded to nearest whole number, finally subtract 1 to get a guess at how many intervals are missing, then tack on a bit of text.
End If
Next cll 'move onto the next cell (cll)
End Sub
You can do what you like between If… and End If; add lines, change whatever, they're not interdependent.