Myself use a 20% rule for Myself ,Is that wrong ?
These are only guide lines .I knows people who gave spent $35k on cables
$15k on power cords alone. The Verastarr Silver alloy foils are = to a awg9 gauge
And every piece of gear just sounded music more resolved and natural noise floor included much lower. Are they worth $3k each ? If you can afford then why not
When the rest of your system is top of the line. It is all relative to what you have ,
Can afford ,and willing to spend . I remrmbrr Kimbers Black Pearls.
6ft Loudspeaker cable statement. - $$ 15,000 and several were sold.
The sky is the limit in Audio.