In our area(s) and experience (which feels more limited as time passes) a rooming house serves a distinct clientele:  a) university students (perhaps a sub-population such as international students); b) work force for a major employer (factory, refinery, mine, hospital) or c) those on the margins (those one step from the streets, the mentally ill {as governments have closed most of the traditional homes and care facilities}, the addicted, etc).  

Every investor's situation is unique, and the mix of available capital of both qualified retirement and non-qualified types, employment type and income, investing expertise, age, and goals will be just a few of the factors that one would need to consider when designing a strategy.A fee based certified financial planner would be the best resource for making strategic decisions.  

I'm self employed in the IT field, I'm looking at this as a retirement plan.Even if I just break even each month, I see it as paying for the house and contributing to my retirement savings.I believe in the concept.

From the perspective of income taxation, that would be less accurate, as rental income is not subject to many of the "self employment" taxes ...

It's 'partly' characterized by the media's new coverage of a hot real estate market (they were just saying 6 months ago about how the market was still slow), employment going up, competition fr properties becoming fierce, out of state investors coming in, etc.Are these the characteristics of 'Concentration' Dale Osborn ?

One of them even had the audacity to ask me to have my employer provide a letter explaining why they gave me such a large pay increase last year and explain that it was worth it.

Looking back: as a landlord its made me more aware to keep window sills in older units cleaner and I always employ a wet dry vac to clean window sills out before I give keys to a new tenant when doing turn overs on apts.

Not having seen it, I can also see where the IRS would be interested in fair market rents as to taxable gains or taxable amounts of benefits not being paid for, much like an employer providing housing and the employee not claiming that benefit, probably along the same lines.....And, there are different tax treatments for financed transactions, so there is another tax issue I can see.

On the personal side it is considered self employment income but I would recommend speaking with an accountant, they are usually very familiar with situations like this and can best provide you tailored advise

I've made my biggest profits from SFR's, both flipping and holding, but I'm not otherwise employed and do all my own work so I have about as much control over things as is possible in this field.