Lumber wholesale prices have dropped but what retailers have learned as Home Depot shared on MarketWatch, as soon as the put lumber on the shelf at the top end price - it sells that day. 

My active investments (which require work and time), I typically achieve returns in a different stratosphere than 3.5% (most of my RE investments are infinite return as they have had all investment extracted). 

Ideally we trap $0 of our investment on a ~$1m ARV (ideally we get some cash out on the refi) and conservatively STR rent for >$12k/month achieving an infinite return. 

Yet, they are all flying off the shelf in a bidding race.What am i missing?

The cherry on top... have yet to pay a single penny of my own money into this mortgage, thus an infinite return on this investment.

I guess I would encourage you to research infinite banking.

Because what is the shelf life of an AC unit?

I have seen many suggest limiting to below a dollar value for for multiple SFR fix and flip properties.There's obviously a lot of opinions and different ways to do it, but one thing I have been advised is that when you move on to a new LLC, don't wind down the old LLC, but let it sit on the shelf for a determined period of time, otherwise you risk taking on the liability of the defunct LLC yourself, which obviously defeats the purpose of your LLC.

Really small kitchen space, ok with Home Depot / Lowes off the shelf fixtures, etc.

If you put no "cash" in, the CoCR is infinite.