I look at the electric, plumbing and HVAC and predict when they may be replaced.

For the ongoing/routine items, I'm less sure - though have a pretty good idea of some routine stuff, like lawn mowing, other things feel like a complete guess, like how many plumbing calls will I'll need per year per unit? 

*Periodically inspect all sinks, bathtubs, washing machines, plumbing fixtures, appliances, windows, or anywhere water may be present to ascertain whether or not there is any water present around fixtures.

Search for homes that have unfinished areas, separate entrances, and plumbing and electrical connections already in place.

You also are welcome to do your own plumbing, taxes, legal work, electrical work, landscaping, etc. 

We backed out of that deal because there was a freeze that hit Texas market, and that freeze caused a bunch of plumbing issues.

to give some feedback, you will need to estimate the cost to repair the house; if you don't know how to do that, we just need some  information of what the house needs and the sqft of the propertyIf the house is, as an example, 2500 sqft, and It looks like you are stuck in time back in the 1980s, but the AC is working,  the roof is ok, and there are no foundation, plumbing, or electrical issues; I can assume maybe a $20 per sqft, so the rehab is about $50K to 60KIf the ARV is 290K minus 10% closing/holding costs, - minus 20% profit - $50K rehab, ideally, in this example, I need to buy the house for about $150K to flip it, but as a landlord, I may be able to pay a bit more, as long as rehab is not too much, and rental is about $3,000 to $3,500 a month

I know there's the inspection period and buyer must perform due diligence BUT it never is normal to research permits for every single plumbing fixture, electrical box, all liveable areas, etc.

We made several improvements to the property when we got it - a totally new gas line, a totally new water line including all the lines from the street and pex plumbing installed.

No claims, updated roofs,plumbing,electric.