Arnie,
Nice looking building! Congrats!
I am not a frequent poster here but could not let your post go by unanswered. Granted, this is simply my opinion but I believe that your colleagues who are in the "max rent" camp are wrong. Real Estate is not a maximum rent or maximum profit business but rather a maximum revenue business. Your apartments are a perishable product. In other words, every day a unit goes by vacant is revenue you will never achieve. You cannot inventory an unsold apartment unit for resale later. In addition, real estate is a very high fixed cost business; taxes, insurance, debt service (really a liability but lets call it a cost for this discussion), payroll, etc. These costs are realized regardless if the unit is full or empty. If two of your four units are vacant then you will still have all the fixes costs associated with your asset. Your goal is to maximize the revenue over a given period. If you attempt to maximize your lease rents then you risk driving vacancy through turnover. Furthermore, turnover will increase costs due to turnover and make ready related items.
Now, with that being said it is possible to have your rents too low where you have very little, if any, turnover but you will not be maximizing revenue. Only you can make that determination from knowing your market and what other similar properties are achieving for rents. And your own comfort level.
Many big operators operate this way through the use of rent pricing software (Yieldstar, etc). Go shop a large (250+ unit) class A property sometime and tell them you want an apartment in two months. Then ask them what the price would be if you moved in next week. Most likely it will be lower then the price quoted two months in the future. The leasing agent or property manager has no say over the rent but is merely reading it off a computer screen. If you ask "what is the rent on a 2 BR" they will immediately ask "when do you want to move in". Large operators use software which have owner inputs that take into account current property occupancy, seasonality, competitive comps, etc to determine rental price. The goal of the software is to maximize revenue over a given period and not necessarily maximize the value on a rent roll for a given unit. Although this is too costly for someone with 9 units, you can still use the same principals in concept. Do you hold out for $550 rent or take $525? If holding out for $550 causes an extra month of vacancy and $525 can be achieved today then you are probably better off taking $525 today. $25 x 12 mos = $300. One month of vacancy would have cost you $550. By taking $525 you have maximized the revenue but have not maximized the rent on a rent roll.
Other industries that operate on a similar basis? Hotel rooms, rental cars, airline seats, etc. All high fixed cost industries with a perishable product that loose all revenue generating capability after the night is over, the day is over or the plane has left the gate.
Hope this helps. While your colleague is off turning units and chasing maximum rents you can be at the beach, golf course, etc knowing that your business might just be more profitable in the end.