It's a lot of trial and error and a lot of learning your tenant base. 

My second tenant left after a brief while, and it took a few months of trial & error to get the now 2 vacant units occupied.

You want to know how much they charge per hour, You ask how long it would take to litigate and what the projected cost would be to go to trial.

And re the clauses in some of your leases about not allowing sublets, that reminds me of my first ever trial which happened to be a landlord/tenant dipsute.

Based on a 2,000-calorie diet, the human body generates about 330 BTUs per hour of heat.

I'm doing this right now as a trial.

For those in Illinois, btw I am not a lawyer, this is not legal advice, I found this from a reputable source online, which explains what I saw happening in court as I described above:The determination as to what constitutes a reasonable attorney fee award is within the discretion of the trial court.  

We’ve built some great systems (by trial and error) to get it to that amount of oversight.

They don't have time to hire an attorney, sue you, get a trial date, file a complaint with HUD, wait a year for a hearing.....

The conversation started as a demand for trial by jury, then quickly turned to a negotiation for settlement, then quickly turned to a very small settlement.