Gyroscopic Investing

At what point does it become worthwhile to move your cash position into ETFs like SHV and BIL considering that there is usually a fee for doing so? It would cost me 2x $7 to do so (Traditional and Roth IRAs), and I'm considering just leaving my cash in the (non-T-bill) money market fund.

Suppose you just contributed your yearly $5,500, and you were already perfectly balanced (25/25/25/25). Do you buy $1,375 of SHV or BIL and pay the $7 fee?

I only buy commission-free ETFs and you should too! But there's still the expense ratio, which at the moment wipes out the dividend on BIL and SHV. I keep most of my cash in SHY and SCHO, which I can trade commission-free and whose dividends pay their for their fees and then some.

I ended up just buying some T-Bills which was commission-free.

I personally keep about a years worth of expenses in a money market account and the rest in SCHO.  The $8 trading fee is no big deal when you only touch the ETF once a year.