As much as you can get ! I have seen competitive pressures drive that fee down to as little as 6% of gross rents, and also get as high as 18% when there is no competition. But when there is no rent, there is no income.
I knew one woman "Kathy" who took 15% and she managed about 75 or 80 units for others . . . . plus about 25 of her own. She was a real treasure. She kept no deadbeat tenants. Kathy kept abreast of what rent economics were doing; and she knew the law and always kept her ear to the ground. Kathy knew who just got evicted down the street; who just got a restraining order; and who just got released from prison. She could also spot a person with a false identity right off, and see through a phony reference.
Kathy didn't take any B.S. from anyone; and she kept her vacancy rate down to almost zero. Good tenants appreciated being in a place with good management. Bad tenants were afraid of her. Now that I think of it, Kathy was pretty skilled as a diplomat in resolving those squabbles that arise between and among tenants in the same building. Mediating a dispute before the police have to be called in benefits everyone; but most Managers will not get involved.
Kathy was willing to get her hands dirty, and could pound a nail; sweat a joint; and also collect back rent "on Pay Day" with ease. She was a bit of a "Bruiser"; but a nice bruiser. If she couldn't fix something herself, she could charm electricians and plumbers (or a Cop) into getting up and doing an emergency "fix" in the middle of the night, when necessary . . . . and these guys loved being responsive when she called. She paid them well for what they did, and paid them quick; but no more.
But Kathy got "burned out" and doesn't do that work for others anymore. If Kathy was doing the management, you were getting a really good "problem free" deal for your 15%. Some Landlords didn't know how good a deal it was until they had got some clown to replace her. All management is not the same . . . . and yes, it's subject to negotiation.
I couldn't/wouldn't work that hard. I'd be shot.
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Dale C. Hittle of GOLDEN RULE PROPERTIES in Glover, Vermont
Where We're Always Striving To Put Together "THE FAIR DEAL"