CV axle DIY?

[Hard_Yaris]

recently after putting on my winter tires i noticed both drivers and passenger sides have torn cv boots. I think they are both clicking but for sure the passenger one is.

I searched the forums and found some useful information, but now need some questions answered.
Is not repairing this going to lead to expensive transmission repairs?
How long can i safely ride with torn cv boots?
While I'm told to replace the entire cv axles with new ones, what other components should i replace while doing the cv axle replacement?
Also curious about changing the transmission fluid, will the fluid come spilling out when i remove the cv axle?

Just want to have all my parts together before taking on what seams to be a monstrous job. Would like to go into the mechanic with some knowledge, or if its a Novice job that i can handle DIY'ing it.

My car has 180K and im looking at rebuilding the entire front end so that i can drive this car for another 180k front struts are about 90k old..

Any help would be awesome!!

Thanks,