Is it better to keep my emergency fund in one account or spread across several?

For most people, one dedicated high-yield savings account is simplest and best — easy to track, easy to access, and clearly separate from spending money. Keeping it all in one place also makes it obvious when the balance dips and needs rebuilding. There are a few good reasons to split it, though: if your fund exceeds $250,000 you'll want multiple banks to stay within FDIC limits; if you want a deeper layer earning slightly more, you might keep the first month or two in instant-access savings and the rest in T-bills, a money market fund, or a short CD ladder. The principle is to keep your front-line cash fully liquid and insured, and only diversify accounts for insurance-limit or tiering reasons — not so many that it becomes hard to manage.