I was wondering how you work with your buildings super?

I have multiple properties and in each I have a different deal, and with whomever I talk to has a different strategy.

Let me take one example I have in nj a 3 family property, I pay a guy to be the super $100.00 a month, the regular month to month maintenance is minimal, he just needs to pull out the garbage-can twice a week, the tenants are neat mostly adults, so there is not much to do on a daily basis.

However the problem starts when  i need to do some repairs. Which repairs should be included in the monthly price and what is extras?

For example if i need to replace a piece of wall with new sheetrock, is that out of the line?

I just took one example but my question includes anything, what should be included in this price?     (I understand that I can write down whatever I want but the question is what's fair)

Also I haven't found yet a written agreement between a management and super...

   Thank you