Carrying cost per day is the number I keep leaving out, and it changes everything

I've been pricing my first deal from the outside for a while and I finally built the daily hold number instead of a lump sum contingency. Interest on hard money at a rate I'd have to confirm in writing, taxes, insurance, utilities, lawn, and the loan's monthly minimum whether or not I'm drawing. On a 210 purchase with 26 of work it comes out somewhere between 165 and 205 a day depending on the lender's structure.

That number changed which houses look good to me, and I want to know if experienced people here actually underwrite this way or if it's a beginner over-correction.

Case for pricing by the day. A 45 day cosmetic scope and a 75 day cosmetic scope are 6,000 apart before anything goes wrong, which is most of the difference between a decent flip and a bad one at current margins. It pushes you toward smaller scopes, sequenced trades, and materials in stock locally rather than special order. It also tells you what a delay is worth, so you know when paying a premium for a faster crew is rational.

Case against. Days are not really the variable you control. You control scope, crew availability, and how fast the market absorbs your finished house, and the days fall out of those. Underwriting per day can make you buy the cheapest fastest cosmetic job in a neighborhood where a slightly deeper scope would have earned 20 more on resale. Also, the days that kill you are usually the listing days after completion, and no amount of scope discipline fixes a slow market.

What I don't know is whether the per-day number actually changes decisions for people running deals, or whether it just makes the spreadsheet look serious.