I’ll also amortize large items like roof over 20 yrs, and then add $100/mo/unit for general repairs.

How much will you spend in repairs on a 1920's house with renters ? 

The key is ensuring the after-repair value (ARV) supports refinancing to pay off the initial funding without overextending.Fix-and-flip - This requires sharp numbers and market knowledge.

Assume a couple of months of vacancy, consider potential unexpected repairs (like HVAC or plumbing issues), and test the numbers with rents dropping by 10-15%.

I am a buyer - my buy box is 200k ARV, all in $150k after repairs, rents for $2000 per month.

Quote from @Basit Siddiqi: I personally would not buy real estate with a retirement account.There are just too many headaches that are not worth the potential increased return.Some headaches when it comes to investing in real estate with a retirement account1) LTV values are less and harder to find lenders.2) Potential to sell or partially distibute the property if you have to do a RMD(Required Minimum Distribution)3) If you run out of cash and have to make a major repair, you may be out of luck and have to sell.4) Having to potentially worry about UBTI(Unrelated Business Taxable Income)I would personally invest in stocks/bonds/notes with a retirement account.I buy deals with cash and use a ROTH SDIRA so there are no RMD's.I buy at huge discounts to retail.

There were a number of issues, but the big one was a "repair" charge they lied about.

I'm in Detroit now for inspections on one and to generate the scope of repairs on the other.

Cash Partnership 50/50 on both the purchase and repairs.

Staying as liquid as possible might also help you handle CapEx, taxes, small repairs, and so on.Let me know if you have any questions—I’d love to help in any way I can!