@Deborah Wodell ok let's first get 1-thing straight: EVERYONE sells, e-v-e-r-y-o-n-e. The only question is *when, *why and *how.
Any with the "I will NEVER sell" mantra, well, this little thing called mortality may have other plans for them.
Real Estate is a river, always moving, always changing, cutting new bank and turning old into bog's. What was vibrant becomes stagnant. Simple examples; Detroit and Austin. One was everything and became nothing, the other nothing and became everything. CHANGE is the 1 constant.
The 1 universal rule is ALWAYS BE ANALYZING.
My first metric of weight I consider is CAP-X. Where is the property in it's life cycle? What expenses are coming to bear? A market can remain strong and an assets performance goes to hell simply from suffering the ravages of time and cap-x. Yes, sometimes it's great to exit a performing asset in a good performing market because your exiting before cap-x comes to bear.
Equity Accrual and Opportunity Cost. I have not heard any speak of the most paramount factor "opportunity cost". Say you got a property at $250k, it's done well over a decade and now your sitting a-top $225k in equitable returns. And it stands a "opportunity" of Pyramiding gains via 1031 into securing 3 similar units in market. You "could" be accruing new equity gains of 3X if sold and made new acquisitions, as well as roll the cap-x clock back a bit. THAT is a BIG "opportunity cost" to NOT selling. If math's hold, that's about half a million $ "opportunity cost" to NOT selling. Because your sacrificing gains on 3 for gains on 1 AND the cap-x that comes with the 1.
Lastly Market Analysis: How does the market stand? Where is it going? What factors have changed? Again, change is the 1 constant so what is the changes now, up coming and on the horizon?
What I do NOT consider is interest rates, that is a horrible reason to follow. For simple fact you're not paying that, your tenants are. All that matters is the performance in total. An older property with low interest rate and into cap-x can easily do much more poorly than a newer unit with double or even triple the interest rate but limited or no cap-x.
So many get the maths wrong in REI.
You, the investor, pay capital contribution to gain control of property, and reinvestments. Tenants pay the rest and ideally, as much of all this as possible, right. Who cares if the mortgage is $2k a month or $7k per month if vacancy is low and tenants always cover that in full?
And when rates are high, competition is lower, meaning cost basis is lower. Rates can change, rates can be negotiated. As saying goes you "date the rate but marry the mortgage".
As for a generational lineage plan, it's best to assume at a future date you will liquidate EVERYTHING, roll it into a fund of some type be it in syndications, W.S. or what-not, and than the heirs will "manage the managers" as this is the most realistic long-term multi-gen inheritance structure. If argue this just do some research on inherited wealth, it does not hold a good track record, failure rate is astronomically high. Hell, Ford's don't even own Ford anymore.....
Summary: Always be analyzing. Don't use singular metric tunnel vision, take the whole into account and always follow the maths.