Is it a fire extinguisher or just an air bubble tank?
A portable plug-in air compressor is more useful. I always bring my Arb with me especially when I do off-roading. My truck has mud terrain tires that need to be aired up.
My LRR factory tires really don't get much "maintenance".........the low pressure lite really is out of a job. At close to 50,000 miles - the tread depth measures 6/32 front - 7/32 rear. (Guess rotation is maintenance)
fyi - new tire tread depth - Tire Rack IIRC - is 10/32.
I know I've mentioned it a million times, but I'm so jealous of how long your tyres last out there. The joys of straight flat roads...Just fitted my 12th tyre at 34000 miles. Must be one of my biggest wear/tear cost items.
I usually rotate my front tyres half way through, so that all 4 need replacing at the same time. But not always, fronts wear alot quicker, on my FWD front engined car at least. I also had a front puncture so replaced the front two early. So yea, 12 tyres 34k, but these front ones will see me pass 40/45k miles with any luck.
We have alot of tight curves here and abrasive tarmac for grip. Awful for fuel consumption and tyre wear, awesome for traction. Safety comes before tyre wear.