Excel VBA Performance

Making Workbooks Calculate Faster.

VBA can be very handy to automate laborious routine task.
But too extensive use of formula make workbook calculate slower and slower, especially when data is huge, and growing.
e.g. Thousand or millions of cells that use "VLOOKUP" formula will make the workbook saving process very slow.

To improve, or optimise, read this

Or another wrap around,
    only activate the "VLOOKUP" formula upon demand.
This example illustrate the technique to