Could you tell that to them on the phone when a buyer calls "you've got to see the upgrades in this house" or put emphasis on the upgrades in your ad descriptions?

I have put most of everything I get out of them back into them to pay for the upgrades and any financing I do is paid back in about a year to 3 years by taking the money from the paid for properties to pay off the others.

That probably wouldn't fly in most places, but here in Portlandia it's a selling point with extra points for being eco.

I lived in this unit for a while so I wanted it to be nicely upgraded.

Further, there is no need to shut-off utilities or pay shut-off fee as you will likely want/need to use utilities during vacancy for potential repairs/upgrades.

This also applies, for example, when repairing/upgrading a rental, your instinct might be to put in nice granite countertops or fancy tile floors, just like you'd enjoy for yourself.

However, we have also found side-by-side multis built from the same plans at the same time (40 years ago) which had received different levels of maintenance and upgrades over the intervening years and had diverged sufficiently that estimates from one were not readily applied to the other.As Bill mentioned, you need to learn to walk the building while "rolling the tape" in your head.

Also, are there any creative ways to do flips if you don't have all the repair/upgrade money up front?

R&M is high as the house is 100+ years old and a lot of small items to upgrade/replace over time.

The fact of the matter is that a computer can not look at recent sales and calculate for amenities, views, upgrades, needed repairs, most recent sales (until/if it is fed the new data) etc.