@Ada Tor The worst thing that could happen is that you have a bunch of musicians in there that tear things up. 

I'm a professional working musicians...I've played keyboard for about 20 years...and I love it! 

I've played music all my life and the idea of the agent cutting their fee is the same thing musicians have heard for years from club owners.

But, I called the other tenants in the vicinity of the musician and it turned out he was driving them all batty.  

We both have W-2 jobs and self-employment income from our respective professions (sign language interpreter and musician/pianist/entertainer.)

Consider turnover costs as a factor (all other factors being good enough)- I am self-employed and can attest that not all self-employed people are created equal (think about a musician vs. a lawyer or investor with his own LLC). if you are truly worried about Couple B's 2nd income, ask for a 2-3 years tax returns showing total income and carefully consider the circumstances and stability of the self-employment (10 years as a piano teacher vs. just starting out).- finally, do find yourself already annoyed with couple A?

I'm a professional musician turned grad student, finishing up a Physical Therapy degree, while still working as a musician (living in NYC area). 

As a musician and entrepreneur, I plan to combine my creative thinking with my growing knowledge of real estate to forge a path to financial freedom.

Musician, painter, photographer, graphic designer, dancer etc. 

I know it’s a lot to ask to meet a complete stranger and have them pick your brain, but seriously, you can order whatever you want on the menu and if you want music lessons, I can offer those as I am a musician by trade (mostly drums and guitar.)