Your tires are good for only 6 years.
The first two numbers are the months the 2nd two are the year.
The eviroment,weather,sun,heat etc.ruins the tires.
It is better to run your tires than let them sit.Even off and in storage they will
deterioate.
They will start having problems,after 6 years.
Its not the tread,but the sidewalls,that break down.
I read this, on several differate tire sites.
So figure 6 tires is 100.00ea = 100.00 A year,thats not bad.
It really feels good to have piece of mind, when you have new tires.
Also get 8 ply tires they have stronger sidewalls,which gives your rv less sway.
(You'll need it when a big rig pass's you going 100 mph.)