[jIM_Ohio]

Back to OP's question- main issue with an EF is that it be in cash based investments which have liquidity.

In some of the specific examples mentioned here (needing a mortgage payment) that transaction has a given date. The other 29 days per month give some flexibility before that date hits.

In other specific examples here (use a cc to cover the expense) that can work on any of the other 29 days of the month too.

The issue is having the cash (assets) to cover both of the above, and to have the assets under YOUR control.

If you use an online MMA, check the transaction fees and compare to the APR on the account. See how reliable the APR is (it will fluctuate, just compare how it fluctuated to similar accounts). If fed drops rates, a MMA will drop the APR soon after (within a day or week).

If you use CDs, check the banks hours. Can you get access to bank 7 days per week? My bank has hours all 7 days. CDs will lock in rates, so if fed drops rates, the CD is paying you the rate which was locked in, not the current rates.

Others might mention using Roth deposits, a HELOC, a credit card, a mattress or something similar.

Weight the pros and cons of each method and emphasize having the assets in your name, with cash you have already made in the account.

I lived for 9 years without an EF and used cc until I saved enough cash to open my EF (and I keep this cash in CDs now). Others here will tell you I lived on the edge. Do what makes sense for you (I maxed out my IRAs and had a high 401k contribution those 9 years, so tell me if I made a bad decision).