A new battery can solve one problem while raising a different question before a smog inspection: has the vehicle completed the checks the test needs to read?
Readiness is a record of completed checks
Readiness monitors describe whether particular on-board checks have run. Disconnecting the battery or clearing diagnostic information can reset them. A monitor that has not completed is different from an explanation of why a component has failed.
There is no universal mileage shortcut
Different checks run under different vehicle-specific conditions. A fixed distance promised online is not a dependable substitute for the manufacturer’s guidance or a readiness assessment. Do not keep driving an unsafe or poorly running vehicle just to chase a number.
Tell the shop what changed
When you call, say when the battery work happened, whether any codes were cleared and how the vehicle has been used since. Have the year, make and model available. These details make it easier to discuss your next inspection step.
Use the current requirements
Readiness rules depend on the vehicle and current inspection standards. Rather than relying on an old allowance mentioned in a forum, let a qualified technician apply the appropriate requirements. The official reference is linked below for readers who want the technical detail.
Plan around information, not a guess
If your inspection is time-sensitive, ask about readiness before travelling. Keep any repair paperwork with the notice you received. A brief conversation first can be more useful than arriving with an assumption that the new battery automatically makes the vehicle ready.
Further reading
BAR: On-Board Diagnostic Test Reference
General educational information. Confirm requirements and testing availability for your own vehicle.