Reducing the File Size

There are several things that you could try in order to try and reduce the file size of your workbooks.
Delete any empty rows below your data.
Check the "used range" on each worksheet and delete any unnecessary rows, to find the last used row, press (Ctrl + End).
The "used range" is only updated when you close and reopen the workbook though.
Save the workbook with the macros disabled, then reopen and enable macros.
Export all VBA modules, close and then import them all again.
Remove the formats from any blank cells. press (Edit > GoTo) special, select "blank". Then select (Edit > Clear All).
Check that you are not saving the workbook as multiple versions (i.e. as "Excel 5.0/95 Workbook (*.xls)" ).
Delete any custom number formats which are not being used or are not necessary.

Remove invisible shapes, compress images, delete hidden worksheets.

LINK "Excel Bloat" to this page.
Formatting entire rows/columns ??
Referencing entire rows/columns in formulas ?? - this is not straight forward are needs more research