This whole discussion has been very helpful for me, thanks to all who participated :)
Let me see if I can sum up the various view points in a way we can all agree with (not likely, I know, but I'll give it a try).
Let's say I buy a house for $50k. It is non-financable and non-livable in its present condition. If I want to make a profit, I have to fix this. There is a minimum amount of work I need to do to be able to retail it to a new home owner. (I assume this is always our goal since we are rehabbers and not wholesalers.) The cost of this minimal rehab is never going to be part of my potential profit. Let's say the cost for this work is $20k. The first question is, what is the ARV on the house if I just do the minimum? For our example say I can sell it for $110k in that condition. So, less closing/selling costs and the cost of borrowing the money (just for round numbers say another $20k), I can expect to see $20k profit.
The second question is, what is the maximum ARV on the house I could reasonable expect to get? Again, for our example, say the max. ARV in this neighborhood is $140k. That means there is another $30k possible profit left in the deal. So, here's the rub: every dollar I spend above the minimum repairs had better either return more than dollar for dollar or reduce DOM. If not, it's coming our of my profit. So, if I can spend another $5k and increase the ARV by $10k, I should do it. But if spending another $5k only increases the ARV by the same amount, maybe I shouldn't, unless of course it has a good effect on DOM.
I would guess that it will always pay to do somewhat more than the minimum if only to increase the curb appeal and sell it faster.
Does this make any sense? If so, would you agree/disagree/don't care?