Thought id chime in, been through this multiple times.
Monitors will only monitor the blow out. I check my tire pressure weekly or before any big trip.
lots of things are made in china and there not all junk (iphone)
Tires in general start to wear the minute their made. rubber deteriorates faster than you might expect. Rule of thumb with automotive tires is now matter what tread wear you have replace at 6 years. Installed custom wheels and tires on my f250. when they wore out i put the original tires and wheels back on for what i thought would be a month. 22 miles later i blew a tire and it caused $2600 damage to the truck. The other side was delaminating and had a large bubble in it.
trailer tires are probably half that. Many boat or trailer manufacturers have moved over to automotive tires. My axis has 18" wheels with "auto" tires from the factory.
You can buy auto tires just make sure the load rating will equal trailer and boat combined weight.
What ever you buy check the DOT #. The last four digits are the month and year the tire was made. Ex. "2216" 22nd week, year 2016. we had to throw brand new tires away at the dealership years ago because they were old stock, slow moving tires......
