This past Spring I had a flat on one of the front tires to my backhoe on a Sunday morning. It ruined the day, plus the day to drop it off and another day to go get it. Two weeks later, on a Sunday morning it went flat on me again. This time was the last time. I had both front tires filled with foam. Cost was just over $500.
Over the summer, my front tire to my small tractor has been leeking air. I started out sliming them when this happened, but Slime has it's limits and it's only good for so long. After a year or two, it's pretty much worthless. New Slime doesn't seem to have any affect on a tire that has already been Slimed. Tubes are the only answer short of a new tire.
Six years of flat tires and 400 hours was the limit. I bought two new tires and had them filled with foam. Coast was $550, and it took just over a week.
Since then, no flats!!!!!!! It's just a nice feeling to be able to start the tractor and go do something without having to deal with filling it up with air, or having it go flat while out mowing.
Eddie