To see if your CV joint is damaged, do the following:

1) Come to a complete stop.
2) Turn your wheel all the way to right
3) Slowly give some gas
4) See if you hear clicking sound coming from front
5) Repeat above except turn all the way to left

If your boot is ripped but you don't have the clicking problem, REPLACE instead of repair the boot only and repack. If you wait until they click, you have to replace the whole CV joint assembly. In another word, if you are fortunate enough to notice the rip without the click, DON'T WAIT!