I have 2 of those as well, but with about 500' of hose on each. The main degrading issue on this
type of cart is, as you suspect, internal rust from water that seeps into the tubes collects and eats the bottom tubes. On
these carts the bottom tubes are not continuous. They join at the middle giving water a way out. Also since this makes the tubes shorter you can more easily pre-treat the inside by spraying in a wax based corrosion inhibiter.
Mine spend the spring and summer outside and after 5/6yrs are fine. The flat free tires are great because they are maintenance free. --- Also note that you can mount the reel pivots to the underside of the tubing to make the reel hang lower. Iv found no disadvantage to doing this.
