Here is my full financial stack — every account I have and exactly why it exists.

Checking account (credit union): monthly operating account. Gets my salary, pays bills. I keep 1.5 months of expenses here to avoid overdrafts but not more — excess earns nothing.

HYSA (Ally): 6-month emergency fund plus sinking funds for predictable irregular expenses (car insurance, home maintenance, annual subscriptions). Currently earning 4.4%.

401k (employer plan): contributing 15% of gross, invested in a low-cost total market index fund (0.04% ER — the cheapest option in the plan). This is the tax-deferred bucket.

HSA (Fidelity): maxed annually, invested in VTI. Never spending it — letting it compound. Receipts folder for all medical expenses in case of future self-reimbursement.

Roth IRA (Fidelity): maxed annually via backdoor Roth. 100% VTI. This is the tax-free bucket.

Taxable brokerage (Fidelity): overflow after maxing tax-advantaged accounts. VTI, VXUS, and a small position in short-term Treasuries that replaced my old bond sleeve. Tax-loss harvested when opportunities arise.

Six accounts, all automated, check in quarterly. That's it.