I don't know how long you can expect them to last. Probably depends a lot on the conditions where you are: salt on the roads, etc. I just replaced my auto tranny and had to pull both axles so I can definitely help you with that if you have questions. The FSM (linked in a sticky on this forum) shows the steps I used but there is one step that I think is not well documented. The good thing about the way the FSM tells you to do it is that you don't have to remove the brake caliper or disconnect any ball joints. The bad is that you are told to drive the left axle out of the tranny with a screw driver but they aren't clear that there is a pin in the way. I couldn't drive mine out so I pulled it out with the tranny. Once I had both parts on the bench I could see the pin the was blocking the punch from getting to the end of the axle. Looking in where the right axle was you can see a pin the crosses the circle and you have to get a small punch or screwdriver beside the pin to drive it out. It kinda looked like the universal symbol for "no" - a circle with a slash through it. HTH.How long do the outer CV boots usually last in a 98 Sentra GXE (autotragic)? 60K miles? 100K? And, how hard is it to pop the axles out to replace them?