How many people typically collaborate on complex Excel files? How do you prevent overwriting each other’s changes?

In my line of work, complex Excel files (financial models, budgets, business analyses, quotes, project tracking, etc.) are rarely created by a single person.

For example, the workflow might look like this:

• One person maintains the source data
• One person modifying formulas or the model
• One person creating charts and presentations
• One person reviewing the results
• Multiple people simultaneously editing different sheets or sections

But this often leads to:

• Files being sent back and forth, ending up as “final_v7_really_final.xlsx”
• No one knowing who changed which formula
• Two people editing the same sheet, forcing a manual merge
• A cell being overwritten and not noticed until much later
• Difficulty comparing “which version is better”
• Difficulty reverting changes after an error

I’m curious about everyone’s actual workflows:

1. How many people typically work together to maintain a complex Excel file?
2. What are the usual responsibilities of each person?
3. How do you avoid overwriting each other’s changes?
4. Has anyone tried version control, comparison, rollback, or even merging for Excel, similar to Git?