You won't be able to "teach" the ECU when to set the P0420. However, you can avoid the type of driving where the ECU conducts its catalyst efficiency tests, which is sustained steady-throttle driving at normal operating temperature. If you do mostly or exclusively local stop-and-go driving the inefficiency code may not come up for a while. OTOH, it's also possible that under those conditions the readiness tests may not fully complete either.
There are extended emission warranties on certain components, including the cat. These warranties are for different terms depending on what state you are in, the info is in a booklet that came with the car along with the owners manual and other documents.