About 44% each from SS and RMDs from IRA (I'm 75, DW is 65 and won't claim until full retirement age of 67). The rest is from a pension from employment at a public university in Texas for 10 years.
Also have a small inherited IRA from my mom (split with my brother, ca. $40 k each) and have 10 years to deplete it (started this year). This year took a larger amount for tax reasons and will do the same next year before my DW starts her SS the following year. Then we'll see, depending on what works best.
Essentially, the money from the inherited IRA and between a couple thousand to $2500 each month from the combined income from the above sources goes into a taxable Fidelity brokerage account that I'm investing myself. Another couple thousand $ more goes into various savings accounts for larger, occasional expenses: eventually replacing our car, medical expenses (mostly dental—our health plan, which is very good, covers most stuff and we can pay out of pocket for those few co-pays and meds we have), household (larger repairs or projects), and vacation.
We also have a small savings account with our regular bank for occasional things that we might need to do and can easily cover this way. Given the small interest paid (B of A), it's not worth keeping too high. We also transferred a big chunk of the amount in car savings to a much better CD with our other (local) bank, just keeping enough in B of A to get better service and fee free.
