Tire sealant is not meant to be a permanent tire repair but sometimes it can be.
Tire sealant is actually meant to get your tires sealed enough to where you can get off the road and then get to a tire shop so that you can have a new tire installed or have your tire patched or plugged.
So you're supposed to use the tire sealant as a temporary fix until the tire can be repaired or replaced and you're not supposed to drive any farther than a few hundred miles or so with the tire sealed with tire sealant.
But I have used tire sealant and drove on the tire until it wore out and needed replaced.
I had a 2 year old tire and got a small hole in it and used the tire sealant and then drove on the tire another 6 years before the tread wore out and needed replaced.
Also make sure to have a spare tire with you, a jack and lug nut tool to remove and change the tire while on the road as that will help you a lot better.