I got better terms (lower fixed rate for 30yrs with no balloon and the necessary costs of a new loan in 5yrs) and lower costs than going portfolio loan, and retained the flexibility to offload the properties individually if needed.

Keep every key tagged with a flexible plastic key tag that uses a clear plastic shield to protect the written label. 

Long-term debt is cheaper money, but its less flexible and carries a bit more risk.  

I would go with month-to-month right now, but that's my personal preference as I value flexibility over incremental revenue. 

As an owner-only business retirement plan, the Solo 401(k) has higher contribution limits, allowing you to build your savings on the front end as well as providing investment flexibility.

For me, I was only ever going to be able to get started part time and needed the flexibility to train, get mentorship, and get support outside of work hours, so there was only one option with enough value but no stigma toward a part-timer.

That will give you time to learn and also flexibility if you do find a property. 

(Unless you really trust the person you're lending to or have some flexibility on that April due date.)

If they cause a lot a damage it may be worthwhile to use the tools available to try getting some of your money back.I recently switched to month-to-month because of the flexibility it gives me.

Just my quick 2 cents on this, I would say the following might be some: Flexibility of termsNo credit impact (don't use one of your Fannie/Freddy slots either)Ability to quickly negotiate and adjust if something comes up where you can't payI'm sure there are more, but those are just a few