Q: Motor mount

I have a driver's side motor mount that has a slight tear in the rubber. It's about 3/4 of the way torn through. I've noticed that the car vibrates slightly at any speed. The mechanic that checked my car says that he does not recommend replacing it, because it's not damaged enough to harm the car. Should I have it changed?

Also, a few months ago, I had both of the front axles changed, because they were a little bent, especially the one on the driver's side, like the damaged mount. A couple days ago, the mechanic discovered that the axles are bent a little again, especially the one on the driver's side, like last time. Could the faulty mount be damaging the axles?

My car has 68000 miles.
My car has an automatic transmission.