Tire Rotations
There are plenty of excellent reasons for staying current with tire rotations. One of the most compelling is that it may be a stipulation of your car warranty to have your tires regularly rotated. Rotation will also allow your tires to wear at an even rate, extending their lifespan. When left alone, certain tires will get far more use than others. For example, many Porsches are rear-wheel drive vehicles, making those wheels work much harder than the relatively passive front wheels.
If left in place without rotation, you'd need to replace the two rear tires much sooner than the remaining two. Rotation ensures even wear among all tires. The tire rotation pattern your technician uses will depend on the type of tire and whether your vehicle is all-wheel or rear-wheel drive. You should rotate your tires every 5,000 miles or so.
Maintaining Tire Pressure
Your Porsche driver's manual outlines an acceptable range of tire pressure for your particular model and tire type. Staying in that range will allow you to get the most use out of each set of tires you own. You can conduct a quick manual check of tire pressure as part of your car washing routine, checking every few months to ensure they aren't slowly seeping air. You'll also want to check the tread occasionally to ensure your tires haven't worn dangerously smooth. A tire check will be part of any thorough car inspection, so your technician can keep an eye on things for you if you're unfamiliar with tire maintenance.