Here's why:Let's say I sign a tenant to a one-year lease, and 3 months in, their personal/professional situation changes, and they break their lease and move out after a 30-day notice (or maybe less).I am required, by law in most areas, to "mitigate my loss" by remarketing the unit, making it rent-ready, and starting up my lead generation machine to get applicants, funnel them into my screening system, identifying good candidates and ultimately leasing them up.

Will it generate good cash flow year round or just a small period of the year?

An STR generating 120k gross will net about 60 to 70k (subtracting insurance, property tax, utilities, internet, commissions, wear and tear, potential damages and disasters).

I think they all work under the table and only listed "janitor" for employment but didn't list an employer.

If you are paying his/her employer, then you need proof they have WC coverage and you need to be an additional insured and be given 30 day notice of cancellation. 

Reality:  not so much.For lead generation BP has been my only source that has worked, but most of those leads only ever want to look at MFH, and I've learned the hard way MFH data is sucky beyond repair in the MLS.No closings. 

The major metros like Atlanta, Charlotte, Raleigh, Jacksonville and Tampa has seen employment diversification, new corporate hubs, demographic shifts and rising rents and income.

The cumulative employment for the metro increased from 1,145,500 to 1,237,200 year over year.

I make that decision not based on how much it is going to cost, because most repair costs are negligible compared to the income it generates.  

Have a good understanding of who they are and how long they have been consistently employed.