Nissan Altima: When do you know it's time to replace CV boots?

Once a year I crawl under the car and spray my '93 altima's cv boots
with silicon. I then wipe it in with a rag. I noticed this year that
the rubber is starting to show signs of fatigue. The car was in
Florida for 6 years and has been in new england for the last 4 years.
If the stearing wheel is cranked, I noticed the rubber encasing is
showing signs of wear with some slight cracking (very slight) of the
rubber. The car has 124k miles on it, and I'm thinking when the time
comes to get it replaced, that I just buy a whole new remanufactured
axle for the mechanic to install. Any thoughts on this? What is the
quality of the remanufactured parts? How long do these boots last,
assuming proper preventative maintenance?

Thanks,
Bill

"jjjsan" <sbcglobal.net> wrote in message
news:talkaboutautos.com... 

How many miles are on the car? I changed one of mine out at 158k miles
after boot cracked, I replace the entire shaft each time and then the other
one after the boot cracked at 172k miles. They are only about 80 bucks each
from autozone after you return the core.