I am trusting you have it set up with a service. 

And then shut up until they talk.

Property management can be great if you are willing to give up a percentage of your gross rents to not deal with headaches, but it's not like you can just ignore your asset.

Have been through a lot of ups and downs throughout the years.

Better if the company has a lot of info in writing that you can absorb to minimize this.

I have one more question whom to write the mail to ?

Fees should be clearly stated in writing, easy to understand, and justifiable.

Some people will push to get the maximum, even if it means they may wind up with nothing. 

Opt 1) utilizing our savings in the brokerage account and emergency fund and pay for it all up front. 

To sum up what everyone is saying and what we do:- notify the tenant to call the police next time to file a noise complaint.- Send emails and texts to all tenants in the building reminding them of "quiet enjoyment" and respectful behavior to their neighbors.- Avoid being the mediator, judge, and jury