Large companies billed incorrectly and overcharged for years. 

The housing board sided with me and we actually had our rent reduced because she found that the landlord was overcharging us rent for 2 years running.  

My property manager has been severely overcharging me for repairs for months. 

Don't rely on the one quote from the GC as many are over-charging for repairs.

Add that to the fact that rents have been rising faster than inflation these past few years and the result is investors getting over charged for PM services.I have seen some PM companies already adopt new pricing structures which actually reflect the amount of work done.  

Originally posted by @Frank Chin:So no matter how strict laws in MA is, I don't think I would run afoul of it.There is a little more to Security Deposit management in MA than just not overcharging the tenant; you have to provide them with the account number and the address of the bank the deposit is kept at, you have to pay them interest at the actual rate paid by the bank or some minimum rate if the rate is not disclosed to them, as well as some other processes.  

Bad tenants will often have judgement against them, so when you run a credit report and see "XYZ Property Management", that is your best clue.The other side of the argument is that some tenants are falsely accused or over charged. 

Slumlords overcharge for property in poor neighborhoods that is kept in poor repair and allowed to deteriorate.A slumlord causes negative viewpoints of a landlord to be painted with a broad brush.  

The tradespeople bill you directly and you can make your own decision whether or not you are overcharged. 

This kind of behavior can happen when a tenant is trying to get out of a lease.If you have a property manager, is it possible they're over-charging you for maintenance issues, to collect more fees than necessary?