For the seller (John) to defer capital gains via a 1031 exchange, the sale proceeds must be reinvested into like-kind property within 180 days.

How much deferred maintenance is needed? 

As long as you purchase at least as much as your net sale and use all of whatever proceeds are generated, you will defer all tax.

Financially speaking the issue is that deferred capex will exceed cash flow over time. 

Also, I can 1031 exchange some of my rentals that I have had for 25+ years and defer the taxes. 

Use a 1031 exchange to defer taxes and reinvest in more lucrative, cash flow-positive properties or diversify into passive investments like syndications.Pay Down Debt: With limited cash flow, focus on paying off the HELOC or smaller mortgages.

Only do turnkey if you have your OWN well qualified inspector who can point out any hacks or deferred maintenance issues.Many turnkey providors are notorious for this.

A 1031 exchange is a great way to indefinitely defer the tax and use it to grow your RE portfolio, and build long term wealth.The most important factor in a 1031 exchange is that your qualified intermediary must be in place prior to the closing of the sale of your old property.

Using a Self-Directed IRA (SDIRA) allows pre-tax dollars to grow tax-deferred in real estate, but limits flexibility due to IRS rules and potential UBIT on leveraged properties.Investing through a Roth IRA offers tax-free growth and no RMDs, but funding limits and restrictions apply.

Especially with the favorable tax incentives offered to buy and hold real estate vs the ordinary income tax you'll pay on private lending.A 1031 exchange would allow you to indefinitely defer all of the capital gains tax you would have to pay, and instead use it to purchase better performing property/properties.