Knowing when to change an oil pump can be difficult to pinpoint. Every vehicle will be different. There are a few things you can check, and things you can do, to extend the life of your pump and know when it's time to change it.
Most new cars will only warranty parts and labor on things like pumps for a limited period of time. In most cases this warranty will be around 12,000 miles. With proper maintenance this shouldn't be an issue for the average driver. Depending on the type of car you have, and your driving and maintenance habits, most people can go 10 or more years before an oil pump fails.
Keeping it Healthy
The best way to prolong the life of your oil pump is to change the oil when needed. Many people think they can drive a few hundred miles over the oil change due date and be ok. The problem with this is as you drive the oil is pulled up through a pickup tube. The oil is filtered through a screen to keep sludge and other particles out. Not changing the oil often enough will cause the process to break down. The oil can burn off, become sludgy and thick, and end up clogging the screen. If the oil can't get through the screen, it can't get in to the engine.
In most cases a well-cared-for vehicle can go between 250,000 and 300,000 miles before a pump needs to be changed.