The problem of data consolidation in Excel files is complicated.
If we want to do it in Excel we cannot do it efficiently.
The treatment as a scattered database is also hard to do.

File consolidation (budgets)

File consolidation (Excel)

File consolidation (unpivoting horizontal data)

File consolidation (registers)

File consolidation (Excel files / basic example)



The related topics:
Budgeting system
Budgets in Google Docs