Love the convertible handle [on garden carts] information. I never would have thought to look for that.
I have riding lawn mowers. So, it just made sense to me to make sure all my carts had that convertible handle. I don't often fill up a cart with stuff so heavy that I cannot pull it by hand but when I do, it sure is nice to hitch it up behind the lawn mower and let the machine do the work instead of my back.

I'm at that age where I don't want to stress the body too much. Riding mowers are great. Also, I have 3 acres of property and sometimes it is just so much easier to hitch the cart behind the mower and move it from one end of the property to the other.
We use the tires that never need refilled too. Our ancient wheelbarrows and our hand trucks all have them. They make so much more sense than inflatable tires. We get ours at harbor freight...it's been so long that I can't remember what we pay for them. I'll have to check prices and see how they compare to Amazon. I've bought car ports from Amazon but never thought to check them for tires!
I don't know if you read my earlier posts, but I actually bought a set of four 13-inch flat-free tires from Harbor Freight on sale for $17.99 each - regular price $22.99. They looked like great tires.
Unfortunately, the Harbor Freight tire hub at 3-inches was too wide to fit on my Gorilla cart hub size of 2-1/4-inches. I either had to buy more tools to cut the HF tire hub to my width or get a different set of tires.
I found a set of four 13-inch wheels on
Amazon made as Gorilla cart replacements - with the correct hub width - and paid about the same price for that set ($19.00 per tire) after a 5% discount at the time of the purchase.
That was cheaper than using the Harbor Freight tires, buying $20 worth of cutting tools and supplies needed for the modification, and then spending all that time and effort to cut the hubs down to size.
I was disappointed that I could not find those flat-free tires I needed locally, that would have been my first choice, but
Amazon had the best option for me.
FWIW, if/when you need to replace the pneumatic tires on your garden carts, you need to measure three things: 1) tire size (e.g. 13-inch for my cart), 2) axle size (5/8 inch for my cart) AND 3) hub width (2-1/4-inches for my cart).
I buy lots of stuff from Harbor Freight, but they did not have the tire size to fit my cart. So, I had to wait 5 days for my
Amazon shipment and then it took me less than 15 minutes to replace all the tires when I got them.
Speaking of riding mowers and tow behind carts, one of my most useful ideas for a pallet project was to make what I call a mobile pallet work bench on a tow-behind cart...
That was nothing more than a pallet with some 2X4's screwed in the underside to fit that particular wagon so it would not slip off when I towed it around the yard. I just put all my saws, tools, supplies, etc... under the pallet in the cart and take them out when I get to the worksite. That same concept could be used on the 4-wheeled carts as well. Just take off the pallet work bench when you don't need it and want the cart or wagon by itself. Very nice.

Sure is better for me to work on that pallet work bench rather than getting down on the ground to work on my projects out in the yard like I used to do. Easiest pallet project ever. Just toss the pallet on top of the wagon, basically. But I used that mobile bench top for most of the summer. Really handy.