@Brendan Harrison Towels ruined by guests' make up is one my pet peeves.

So pet friendly 1/1's rent within hours usually to grad students who stay year-round for their entire program (years).But to add to the thread, look at your local zoning.  

We never saw extra rent costs per pet, but we tried it and liked it, and now see it more from others.Water is the ultimate responsibility of the owner in our city, so we want to include it in rent.

Every day brings new projects to deal with: you'll have maintenance requests, personal requests, pet issues, parking problems, utility hassles, clean up duties, staff conflicts, and many many more things to keep you occupied.

One time as a 1-year lease was expiring I waived the monthly pet fee if they were to agree to another 1-year term as opposed to going month-to-month, but I wouldn't do that again. 

I cant be here too long, I have to get down to the pet store to get more tax deductions!

My lease holds the Tenant responsible for ordinary pet control and that would include a dead mouse under the stove.

If you add clauses to your lease that tack MONETARY penalties to unauthorized occupants, pets, smoking - then you WOULD be able to evict for non-payment, no?  

I don't know about MA laws, but if it is in their current lease about pets, then you have to honor the current lease. 

The previous landlord's manager didn't charge him for any pet deposit!!!