No. Sometimes the combination lock has some problem that prevents or makes the manipulation process almost impossible. There are also combination locks that are specially designed to prevent this type of attack.
Manipulation, as it is portrayed in novels and movies, has some truth to it, but that's it. The use of a white glove by amateur cracksman Raffles, for example, is totally unthinkable, in the real world it would hinder all efforts making the manipulation totally impossible.
Yes and no. There are cases where this instrument has made the day. But in most cases it serves as a very important support tool for the other senses that are used, which are sight and touch.
The sense of touch. The manipulator has to carefully hone it to a feather sensitivity with many years of effort and practice.
The impatient one may learn some theory, have a little success here and there, but most of the time his efforts are going to be almost null. The most important thing to be successful is patience and endless practice.
There are various organizations that give training on the subject. There are also some technical books out there that are about manipulation.
The technician mainly depends on feeling, seeing and hearing. In those cases where the combination lock can't be manipulated for one reason or another, a good safecracker is equipped with privileged technical information, precision optics and highly specialized drilling equipment.
The most experienced and dedicated safecrackers usually have privileged technical information and work with highly specialized tools and equipment that guarantee minimum damage to the equipment.