You have to consider where the pipes will go for both water supply and drain, where the shut-off valves will be located, whether a window or skylight is present or whether exhaust fan is needed, where the vent for the waste will go through the roof, whether you have electric wiring that can accept a GFCI (old house might only have two conductors on many circuits, lacking ground wire).

I assume the plumbing (waste line, supply lines) for the sink needs to be re-routed... right?

We shop at mom and pop discount supply yards.

My market has less than a 2 month supply of properties under $100k, so there isn't much possible "inventory" for them to control, and most of that is in areas I wouldn't touch.

My point about the inventory just goes to the general supply/demand.

Do you expect a over-supply of rental which will bring down the rental price3.

Your mortgage will remain constant but taxes and insurance increase and labor rates, materials and supplies will probably double.

I'm wondering how the supply of bank owned properties is going in your market.

We have maintenance install the washer and dryers so they are hooked up correctly.We use teflon tape,the steel braided hoses wit the high quality washers on the inside.Where the discharge hose goes into the drain we install a strap to the wall so the discharge hose won't fall out when draining and leak.Even given all that if they have an old washer it can give out and water can be released.The simple fix is a drain pan under the washer with a pipe that ties into the discharge pipe in the wall.All of this will cost about 40 bucks or so not including labor.Well worth it than cleaning up a huge leak causing massive damage.We also check the hot and cold water valves the supply lines hook into from the washer.The valves might be gone and partially leaking.Also if the tenant installs the washer and dryer they might over tighten fittings causing bent pipes and damage or under tighten having leaks.Been my experience with over 20 units on a 30 year old building.

In development cycles there is a under supply,sweet spot,and OVER supply.A certain asset class can be over built and it is often times a race to market on who wins.If your project takes to long to complete and the market gets saturated by that time then you will have to reduce your anticipated rent rates and cash flow projections to bring in new tenants or you will have to spend more on amenities to justify them paying a premium price.Either way it will cost you more money.