THE 10% RULE promises a simple limit on car spending, but it doesn't say 10% of what. So you can't check your own car without clicking. The red Toyota is the kind your neighbour drives, so the rule feels like it's about you.
How the packaging works
Title
'(By Salary)' promises a figure scaled to each viewer's pay, which is exactly what a percentage rule gives them.
Thumbnail
Naming a rule gives the answer a handle viewers can remember, and Humphrey's knowing smirk while pointing at the car suggests plenty of buyers break it.
Remix this
If your advice boils down to a ratio, name it as a rule in the thumbnail but leave out what the number applies to. Point at the thing it covers so viewers start doing their own maths.
The transferable lesson
Name the rule, but hide what the number applies to.
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