Knowing how to properly manage a flat tire is key in protecting you from harm and unnecessary expense. Use this list of dos and don'ts as a guideline:
Don't deliberately drive over sharp debris if it can be safely avoided...an ounce of prevention is worth a pound of cure.
Don't swerve around debris to avoid it if it puts you into oncoming traffic or in the path of cyclists and pedestrians. That would be trading up from a moderate problem (flat tire) to a more serious one (collision).
Do briefly do a visual check of your tires before embarking on any trip so that if you do have a flat, it doesn't come as a nasty surprise. This takes seconds, literally, so it's not something you have to build extra time into your commute for.
Don't take off for work or home—especially if it involves highway driving—knowing you have a flat. Doing so increases the risk of you being involved in a collision. It's also damaging to your wheels.
Do pull off the road gradually and safely when you realize that you are driving with a flat tire.
Do check your spare to ensure that it is adequate for replacing any flats you may encounter. Sometimes it is the case that the spare itself is damaged, which leaves you in a bind if a flat does happen.
Do re-stock your spare once you've used the old spare to replace a currently damaged tire.
Don't assume that the damaged tire can be patched up and re-inflated. If it is a slow leak, then there is a good chance that repair and re-inflation will be adequate. However, if there is a puncture to the tire wall itself, or if it is an issue of the tire tread wearing out, then replacement will be necessary.
Don't assume you have a flat simply because you drove over debris, especially if there are no signs of deflation. Sometimes debris may just leave an impression in the tire without actually puncturing it all the way through. If there isn't any air leaking out, then there isn't a need to replace the tire.
Do check your valve system to ensure that there aren't any leaks there.
Do keep a gauge in your glove compartment to periodically check your tire pressure, and ensure that your tires are inflated at the recommended levels indicated on your vehicle doors. Making a habit of doing this at a gas station will allow you to adjust your tire pressure as soon as you notice it is off, decreasing the likelihood that you'll forget to adjust it later.