My personal experience too and this is for those that do not plan on owning them forever and willing them to your kids or next of kin at a stepped up basis.but for those like me that were thinking hey I will own these 7 to 10 years take the write offs then sell retail..I did all that sold retail but what I was not thinking about is that a 10 to 14 year old home even though I bought them brand new.. to sell retail   what was acceptable when I bought them  tile counter tops  black appliances etc etcnow retail buyers standard is granite stainless  new paint 3 colors floors perfect etc etc.so it was costing me 20 to 25k per home to do a retail up grade to sell them for retail prices.. along with cap ex ( which in my case was minimal) since these were only 10 to 14 years old.. but then roofs being replaced because of hail that cost deductible.. and so on and so forth.. the cost of owning and keeping these nice is just more than you can raise rents in most markets.. that's my experience I got top rents in the day but they never went up much during the 10 to 14 years of  ownership.. just like I see modest type rentals that rent for 700 to 900 those rents have stayed pretty constant for the last 20 years .. and prices to fix stuff has gone way up.. 

It psychologically tricks you into paying your fixed rate low interest mortgage off faster with a higher variable rate HELOC. 

We knew exactly what items we needed (including size and color, paint color schemes, countertops, etc.), and exactly what work was needed to create the vision, and we worked those costs into our construction estimate.However, you are talking about a House Hack or a BRRRR, in which case you just need to get the property into a habitable state, with some flourishes thrown in to make the place more homey and attract renters.

Next week we begin to pick exterior colors, and get started on the interiors. 

So where I particularly need advice:The outside... what is a good color scheme?

I have verbally told my clients the information but I think I will use your list (with attribution) :):)My short verbal spiel would be 1) handy owner occupants don't need to cash flow or make money / profit and 2nd will you have a dumpster onsite the day of closing with day labor for the demo, know EXACTLY which electrician, plumber, flooring, cabinet guy, sheetrocker.....that you will use and when will they start, the PART NUMBERS for the cabinets, flooring, paint colors, doors, light fixtures.....

Studies have been done on the psychology of cash back credit cards... www.thesecret.com published an article in 2010 that says "for every 1% in cash back rewards, the cardholder spends 10% more..."

And 45 days isn't a lot - although honestly these days real estate has become a commodity and I'm observing that the 45 days is more of a psychological than a structural hindrance for a motivated investor. 

Kiyosaki :) The Guy has made millions by telling people that the color of the sky is blue.

We also use the same paint color for all 4 units.