There are many presentation skills straining courses and it can be really good to do a selection as they may teach you different things.
Knowing how to present well is a great advantage because it will teach you ways to come over clearly and strongly which means that if you are selling a product or an idea you will be able to make more of an impact.
If you are a nervous speaker then this sort of thing will be especially useful to you because it will give you the skills that you need to harness the energy and confidence to get across what you need to do so.
If you have few presentation skills and have to speak up in meetings then having some training will really help you to know what to say and when and give you the confidence to speak up.
If you have to do actual presentations, then it is always good to pick up extra tips as to how you can come across better. If you have not done a course for a while, you may feel that you do not need one or not like the idea of having to learn new ideas.
However, it is well worth giving it a go because you should find that you will easily get back in to the habit of learning again and you will gain a lot of valuable knowledge.
Once you learn the skills needed to speak better, you will feel more confident doing it and the more you do it, the more your confidence will grow and you will improve more and more.