As every good diver will know buoyancy control is not a part of diving - it is diving !
Many people sign up as divers to do buoyancy speciality courses, while others say that there should be no need for this if you are trained correctly in the first place. It is a topic for lots of discussion between divers and considerable debate.
Good buoyancy control is essential to good diving. That feeling of weightlessness, the ability to ascend and descend effortlessly, to be able to glide at will without touching or disturbing anything, are all why we want to be good divers and have good buoyancy.
So should we have to do extra courses to improve our buoyancy ? The answer is that it can't be anything but a benefit for most divers. Buoyancy control should be an important part of any entry level course, however there is always plenty of room for improving your skills.
Any entry level course should leave the diver with the fundamental understanding and ability to control their own buoyancy to a good level. This then like any new diver is then developed purely by time spent in the water putting all they have learned into practice and so further enhancing their buoyancy abilities. Divers who cannot control their buoyancy should NOT pass their course, unfortunately many Instructors consider buoyancy as just another skill to tick off and don't spend the relevant time or use the right methods to teach it to the right standard. This is when you then have divers who come to you complaining about their poor buoyancy or tell you they need more work on it.
So an extra buoyancy course is a great thing for many divers who have had either a substandard entry level course, or who want to take their buoyancy control to another level quickly, or for those that haven't dived for a while and want to use it as part of a refresher.
If Instructors do a good job of covering all the required elements on the entry level course divers should have a fundamental mastery of buoyancy control. Divers should be able to maintain their position in the water throughout the dive. This does not mean that there is nothing more that people can learn, even the best Instructors cannot teach every aspect of buoyancy control during the entry level course. There is always room to improve and this can be gained by putting it into practice with plenty of time in the water and by completing a buoyancy speciality course.
After this your buoyancy should be another diving skill that you have to worry less about and your control in the water becomes more and more natural with every dive.