No, the boot has nothing to do with any EAS problem.
Yes, you can replace just the boot. Note that the front struts do not have one at all... Also note that the rear half shafts (drive axle from the differential to the wheel hub) rub against the boot when the boot is flexed into the rubbing position. With a year a new boot will get thinner and worn and finally tear apart at that small spot. Within a year or two from then, the whole thing can finally come apart.
I am not sure exactly what height is required to cause the contact between the bot and the spinning axle but I expect it is during access mode or when lowered.
Now, most people cannot drive at speed while lowered but if you have an aftermarket tool to allow driving while lowered, then you could cause this to happen more quickly, as mine may have. This is a hunch, not proven.
Anyway, unless you go off into lots of mud and stuff, it probably not all that important to replace the boot.
If you need a new strut, it will come with a new one anyway.
Check out Arnott for an alternate source of air struts that may have some parts that are better than the genuine or oem versions available.
