Meaning of the word "every miller draws water to his own mill" in English

What does "every miller draws water to his own mill" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

every miller draws water to his own mill

US /ˈevri ˈmɪlər drɔːz ˈwɔːtər tuː hɪz oʊn mɪl/
UK /ˈevri ˈmɪlə drɔːz ˈwɔːtə tuː hɪz əʊn mɪl/
"every miller draws water to his own mill" picture

Idiom

everyone acts in their own interest or looks for their own profit

Example:
In business, you have to be careful because every miller draws water to his own mill.
I'm not surprised he recommended his brother's company; every miller draws water to his own mill.