Design decisions that decide how bad an incident gets.
A compromised email account is a master key — recover it first, then evict the intruder's persistence, then survey what else it unlocks, in exactly this sequence.
Putting IoT gadgets on a separate Wi-Fi network means a compromised camera can't reach your laptop — and every modern router already has the feature, labeled guest network.
A firewall filters network traffic by rules — allowing expected connections and blocking unsolicited ones — and the one built into your OS and router already covers home users if left alone.
Most breaches exploit flaws fixed months earlier — a simple patch routine of automatic updates plus a short monthly checklist closes the gap for homes and small offices.
A hardware security key proves your presence with a physical FIDO2 device no phisher can clone — buy two, register both, and phishing on your key-protected accounts is effectively finished.
End-to-end encryption locks a message so only the recipients' devices can read it — but many services that look encrypted actually keep a key, and knowing the difference decides who can hand your data over.