I see a lot of posts where actors want to continue their training after they did their major training; in university or conservatory. Is that really necessary?

Training never stops! Denzel Washing, Halle Berry, Leonardo DiCaprio just to name a few are CONSTANTLY training when they're not working.

Just because you finish a university or conservatory, doesn't mean that you know everything and thus can stop training. Acting is no different from being a doctor or lawyer. When you finish medical school or law school, school doesn't end. Every few years, doctors and lawyers have to go back to school to keep up with the current trends. As an actor it is important that you're at least taking refresher courses to stay sharp and focused.

I agree with El you can never learn to much. When I was younger I would remember my ole man saying, "You can always learn- you can even learn from a dummy". Funny as it may sound it satnds true. Lots of times they may take a class as a fresher. Acting is always changing, evolving so you have to saty on top of your craft.

Yes, abosolutly keep taking classes. Unless you are constantly working, because that is on the job training, you should never let yourself get out of practice.

I have been busy thi slast year, so I've gotten away from classes, but I think I'm going to try and start again soon.

Sure, its the one thing CD and agents want you to be doing, I don't agree that you're still learning, other than from yourself. But, its your job and if your not acting daily your not prepared. You may know everything you need to know, but when its not being practiced regularly you are slower than say the people you may be auditioning against. However I feel like some of my good friends that pay to do monologues at class, should just join a group or troupe, its really about being quick and trusting yourself. If you don't think there's anything to learn, try teaching, at least you will be acting daily.
Let me know if you want to join my acting group, we meet, do scenes, tape them. There's just no teacher, just actors sharpening their tools.
cheers