When validity starts
Understand installation, first-network-connection and purchase activation rules before using a plan.
Use the rule shown for your plan
Starts on installation means adding the profile starts its clock, even before arrival. Starts on first network connection means the clock begins when it connects to a supported network. Starts on purchase means the purchase begins the period. Do not substitute one rule for another.
If the rule is unavailable, ask support before installing or relying on an activation date. An installation guide does not determine your plan's rule.
Allowance and expiry are different
A plan may run out of data before its validity ends. An expired plan may still show an unused allowance. Use the profile's reported usage and expiry when available; a plan's duration alone is not an exact expiry date. Turning a line off or deleting it does not establish that its clock has stopped or reset.