If you fill the tire with fix a flat it usually ruins the tire However, for a lasting fix, you should seek professional repair or replace the affected tire. Do not just keep filling up the tire with that bullshit
Fix Repair
Tire shops can repair small leaks with plugs, depending on location of leak
Find a used tire shop, they usually have great used tires and will repair or sell you a cheap halfway used tire
If you go to firestone or one of. Throw a jack underneath so you aren't pinching the sidewall Now the can won't be fighting your residual air pressure, and more will go in Drop the car off the jack and quickly go for a drive
Alternate between 25 and 60 mph as much as you can This flings the sealant into all the corners.