Here a few stats:
Firestone Transforce HT
Miles 12,800 as of 02-06-22
Starting tread depth per Firestone transforce HT manufacturer info 11.9mm
Front tire tread depth 9.5mm (80%)
Rear tire tread depth 7.5mm (63%)
Never rotated the tires, 60psi cold, about 60% trailer towing 5-8klbs, 9x8.5ft frontal trailer area.
We just crossed the rocky mountains, CO in a snow storm towing a 28ft travel trailer, constant winter driving here in MN, no problem.
I wish the tires would not wear that quick but I am not willing to spend money on new tires just because the Firestone HT are not as good as Michelin.