I'm going to try leasing the place out myself again, but if I'm struggling, I will hire property manager. 

Why are you communicating with the tenants if you have a property manager?

Tenants should certainly take responsibility for maintaining the property and promptly informing the landlord of any maintenance concerns.

@Albert Gallucci as many have pointed out, in the commercial space of 100+ apartment buildings and offices, property classes have some pretty decent industry standards.We started applying these to 1-4 unit properties around 10 years ago, which you can verify on our blogs, because we saw too many newbie investors not properly taking into account things like, neighborhood status, tenant pool, property condition, etc.Unfortunately, there's no industry standard for this, but you can use some basic logic to think your way through your own Classifications.

If they change their mind, I put the property back on the market and look for a new tenant.

The property is only worth what it is worth - what the seller needs to make is irrelevant.

Managing tenants is probably the most frustrating task of all the task associated with owning rental property.  

If your tenant is violating the noise ordinance, they will be fined.

Quote from @Josh Otero: Hi BP community, I know you've got some crazy tenant stories and I want to hear it.I'll go first:1) I was managing a 5 story apartment building and a dog fell off the 4th floor balcony because of the owner not paying attention.

This will be my first home purchase, and I am aiming to invest in multi-family properties.What should I be aware of when purchasing a multi-family property?