CV boot - joint question

I have a 1994 Nissan Sentra approx. 67,000 miles. Yesterday afternoon heard a knocking/clicking sound upon making a right turn - about 5 turns later, there was a noticeable increase in the severity of the sounds. Was hoping it was some plastic or something. Got home and saw an obvious break in the CV boot.

question is. Any rule of thumb on how long one can drive with a ripped boot without damaging the CV joints.I will obviously take it in ASAP - I figure if I take it in they will want to charge me to replace boots/joints and all - any way to tell if there is damage to the joints (given that I don't have the ability to put the car up in anyway)?

as a reference the noise started yesterday afternoon - a few light noises then a couple of really gnarly sounds probably drove on it about 5-7 miles with the noise eventually occuring with nearly each turn (the severity of the sound seemed to be directly related to how hard of a turn I made - really wide turns little to no noise but one sharp turn sounded quite bad)

mahalo.