I never trust someone else’s Excel file until I check these 5 things

I never trust someone else’s Excel file until I check these 5 things
https://www.makeuseof.com/i-never-trust-someone-elses-excel-file-until-i-check-these-things/

1. Check for external links before anything else. A file that quietly leans on another file
2. Unhide every row before trusting totals. Gaps in the row numbers give it away
3. Spot numbers that Excel treats as text. Left-aligned digits that SUM skips
4. Reveal totals someone typed by hand. A total that never updates
5. Catch the formula that breaks the pattern. One cell, one different reference
6. Make the next person’s audit shorter. What I change in files I send out