Petit test
Guess first, no penalty. You save a bank rule: any line with "AMAZON" in the description goes to Office supplies. What happens next month?
A bank rule tells your accounting software how to categorize matching bank lines on its own. Most accounting software, including QuickBooks and Xero, has them, and AI chat tools will happily suggest new ones.
A good rule saves hours. A bad one repeats its mistake on every matching line until someone looks. Fix a bad rule after three months, and you have three months of lines to re-code.
So test every new rule against the last three months before you save it. How many lines does it catch? Are they all the same kind of spending? Make it as narrow as the data allows, and have it suggest a category for your review rather than approve on its own.