My employer offered 401k plans so I instantly took that on.

I am collecting my rent through Zelle and it is an instant deposit without fees.

I also attempt to have all of my tenants set up autopay  on that website so I can see instantly if anyone is delinquent or if their payment is in process on the first or third depending on the lease. 

I've focused more on the former for a nice combination of cash flow and instant built-in equity when complete.

Voila, instant AC.Measure the window opening before buying a window AC. 

And be able to accept instant bookings.

Sometimes the Police Officers damage the house on drug raids (making your nice rental into an instant Fixer): https://www.youtube.com/watch?

I think a lot of people get so focused on instant expansion that they bring on partners and it dilutes their holdings long term.

So as you develop the relationships, I would recommend developing a system to instantly make offers that you know meet their criteria (with phone, text, email approval).

They get a receipt and I get instant notification time stamped already in digital format.