To the owner it's quantifiable -- $50 per day in lost rent for 4 days equals $200 lost.And I am a former Yankee living in Florida, so I guess I can relate to your response :)

.#5 Practice, Practice, PracticeWalkthrough potential rehab properties (or find properties virtually online) and practice creating detailed scopes of work, quantifying repairs and estimating rehab costs for the projects.#6 Get Your First Rehab ProjectYou can practice all you want, but ultimately you will learn the most about estimating rehab costs by actually rehabbing a house.

You can't quantify everything.

The investors have to quantify risk the best they can and reach a hopefully well thought out and informed decision.So in the beginning investors do not like to spend money so even active partners can say attorney is expensive we don't need them etc.

Think of this as the baseline (lower bound) quantifiable return. - However, it's more than that.

2) Quantify all of your assets.

@Jack Sun do you have quantified goals and objectives in terms of your total ROI?

Same thing said in two different ways.Remember what IRR is most useful for: comparing one real estate opportunity against another, because the cash flow (in both directions) and the timing of the cash flow, varies from one opportunity to another and IRR provides a way to quantify that performance.  

Pay up for a better deal which even though it might be more expensive, you can quantify the risk and there's other factors that make the deal more attractive (better submarket, better rent growth, less CapEx, etc)

Is the knowledge about any given market and neighborhood quantifiable?