Hi,
I've had 3 cars sealed in Glare as part of a detailing package.
It's suggested it will last for up to 5 years due to how it bonds to the paint at a molecular level. Personally I will get it detailed way before then. That said it truly is fantastic stuff, I'm incredibly anal about tar on either my wife's Red Colt CZT or my Steel Grey edition 30.
I wash the bodywork every 2 weeks and have yet to find any tar that cant be removed by a lambs wool mitt even on the lower door sills.
The beauty of the product is that you dont/should clay/polish wax afterwards.
If I run the back of my hand across the panels they are perfectly smooth even 4 months after the application.