I always buy tires in sets of 5 and use the spare in the rotation using the diagram in the owners manual.
Every manufacturer has a specific rotation guide per their vehicle for a reason.
Only use what they recommend and not what a random universal poster at the tire shop suggests
Due to the road crown, our rigs tend to wear the left front tire slightly faster than the others, so upon the rotation interval, it gets tossed in the spare position to get a little rest
For the same reason, on the RHD rigs across the pond, their rotation diagram is the exact mirror opposite of what we have
I also have my own specific routine when it comes to brand new tires.....
The top layer of the tire always wears a little faster, so I do the first 5 rotation intervals every 1000 miles.
After that, I do the next 5 rotations every 3000 and after that, it gets done every 5000 miles for the rest of their lives (I know, OCD much?)
This pretty much lets each layer of tread wear evenly as possible for each of the 5 tires
I know it's hard to believe sumthin this simple what make a difference at all, but I did manage to get 120,000 miles out of my BFG KM Mud terrains and over 100k out of the replacement KM2 MT's
BFG MT KM2 vs KM treadwear?
Deja Vu with KM2's
Best of all, they still had enough tread for me to sell them on Craigslist for $100 bucks a pop
Currently running 35" D-Tracs with over 100k miles on them and they still look to be in great shape with plenty of tread