Usage limits are the caps, quotas, or allowances that control how much of a service a user can consume. In SaaS and AI products, they may be measured in requests, compute time, messages, credits, or token volume. These limits matter because they protect service availability, control cost, and prevent one account from monopolizing shared resources.
In cyber security, usage limits become a target when attackers steal an authenticated session instead of a password. A hijacked account can be used to spend the victim’s quota, burn through paid credits, trigger overage charges, or degrade service for legitimate work. That is why usage abuse is not just a billing issue; it can be a sign of account compromise. Defenders reduce the risk with session revocation, device cleanup, multi-factor authentication, and monitoring for unusual consumption spikes or access from new locations.