Tenants who game the system like this can make a landlord's life miserable and eat up loads of time if they file complaints, even if you eventually win.Since you inherited the tenant, it seems likely that whatever damage the little rats are going to do is already done. 

They will make your life miserable (or shades of grey of course).2) Have you done this type of busines before? 

If they don't then just move on because they are lowlife scammers or just Contractors that don't know how to run a business...neither of which you want to do business with.Take as long as you need to to find the right GC, because with the right guy you will smile all the way through the project, and with the wrong guy, you will end up in court, miserable and broke.....

We failed miserably and I ended up needing to shift the stairs back for headroom/landing requirements, bring in a structural engineer to sign off on work, redoing the plumbing rough-in for tub for fire wall separation between units, constructing a new 1 hr fire wall in basement, etc.

Eventually, they will find out, and can make your life miserable.

I failed miserably because I did not understand the difference between investing and speculating.

I've tried four different agencies over the years and they all failed miserably.

If the HOA is against it, they can make your life miserable.

It didn't hurt the overall profitability, but I would definitely be more mindful of this with future purchases.Lesson 3: Don't tear your whole house apart while living in it unless you want to feel slightly miserable.

Name your economic cycle, people played Eeyore's favorite tune "everything sucks, nothing works, it's all miserable, everything is bad....".