You're spending a bunch of time dealing with bizarre problems, and then eventually they are demanding to be let out of their lease because of mold or threatening to contact the city because the unit isn't habitable - when if they were just on a M2M, they'd simply give notice to move out.I get the idea of trying to time your leases so people won't move out during the winter, but there's not guarantee a tenant won't need to move then, anyway. 

At this time, the plumber (now his wife joined the conversation) became irate and cussed out our property manager, even threatening bodily harm to him.

Now he has sent the PM and Us a threatening letter to take us to court over his security deposit and damages.

@Jonathan S. unless this is deal of the year or something I'd say you should be commanding market rate at the very least or walk away or at least threaten to do so.

We had one put in a small blow up & I found out when the bldg inspector jumped all over it threatening compliance fines.

The one thing that popped out at me is : be sure you have rental Property liability insurance - i would not be surprised if these tenants start threatening legal action for injuries caused by an unsafe dwelling. 

At some point the tenant might ask for a rent reduction or even to threaten to take the item they installed if the relationship sours when they move out.

Even some of my residents didn't bother to apply for unemployment until a week ago or didn't bother applying for rent assistance.I have had multiple tenants get very angry/threatening with me because we "weren't being understanding" even though we gave payment plans to everyone that asked.

My worst most filthiest disgusting tenants who caused me the most aggravation & called me screaming and threatening started out complaining before they moved in with small stuff that didn’t need to get fixed. 

Current as-built drawings, plans & specificationsDescriptions of buildings, physical aspects and systemsSite Plan (with dimensions and identifying tenants and vacant locationsPhase I and if applicable Phase II environmental site assessmentProperty Condition ReportStatus of ADA compliance (including ADA plans)Warranties (HVAC, roof, insulated glass, etc.)Existing exterior, interior, and aerial photographs of PropertyFloor plans with tenant location (CADD/PDF files)Any and all Leases and Tenant correspondenceAny and all Service ContractsGeneral Ledger for the past 3 yearsThree year history of delinquency and bad debtMost recent detailed billing statement for all TenantsTenant ledgers for previous calendar year & YTDCertified Updated Rent Roll and Certified A/R ScheduleList of security deposits and prepaid rentLeasing update (pending deals, LOIs, renewals, lease-up projections)Future Tenant improvements and leasing commission obligationsThree year history of tenant improvements and leasing commissionsCurrent year detailed operating budgetYTD budget vs. actual analysis for current year & 2 prior yearsThree years of operating statements (revenues & expense) historyCapital items/budget forecast (3-year projection)Three year history of capital expendituresProperty Tax bill for current year and previous 3 yearsCurrent Insurance CoverageThree year history of insurance claims and incidentsTenant’s sales volumes for at least 3 yearsThree year occupancy historyExisting appraisal report(s)Confirmation of ZoningCertificate of occupancy/use permitsStatus of pending litigation and/or threatened condemnationMost recent title insurance policyMost recent as-built surveyCAM Reconciliation for prior 3 years