Question about property mangement

[Mike Winters]

Hi I am a nu-bee so this question might be naive. A property management company averages about 10% fee per month. On a $1200 rental that is $120. What can the company offer that is worth that amount of money per month. What do they do besides answer the phone. I cannot see them doing additional services without additional charges. 

I realize I might be missing something so would appreciate some "schooling"

Thanks in advance