How often should you train your dog?

So you have a puppy or a dog that you would like to train. We know that training should be consistent to be able to work, but sometimes even dog training experts cannot say how much training is too much. Let's see what are the general "rules" about dog training.
What can determine how much training your dog needs?
Pay attention to these specific dog features when making a training schedule:
#1 Age
Training shouldn't be the same for all dogs. Age is very important and it can determine how many sessions your dog should have.
Puppies are excited, eager to learn and full of energy. That doesn't mean you should over-train them! Intense training sessions are not a good idea because sooner or later, the puppy will act like a - puppy - and training will lose its strength.
Don't forget that dogs need to have some life experience to be able to train them correctly. That said, don't start too early.
As for the older dogs, then definitely can be trained and learn some tricks, too, but don't forget that they maybe have some medical conditions that make them unable to train intensively.
#2 Ability
Before increasing the number of training sessions, or the intensity of it, think about what breed is the dog you are trying to train.
Some breeds have natural predispositions to act in one way and training it to be the opposite can bring stress and boredom to the dog. Just don't set your expectations too high. For example, if you want to train a dog to be quiet, you should know that there are breeds with natural tendencies to not bark as much.
Keep in mind the abilities of your dog, and don't force it against them.
Basic tricks you can teach your dog today
#3 Boredom
Sometimes you just have to finish for the day. Too long or too intense training sessions can become boring to the dog, and he can become easily distracted and prone to making mistakes.
Owners sometimes punish dogs for that, causing even more stress and distraction. It can become a vicious circle.
So, take a break or leave it for another day, when you and your dog rest and regain energy.
How often should you train a dog?
When it comes to the number of sessions per day, less is more. Several research papers tell us more about the intensity and number of dog training sessions.
Meyer & Ladewig (2007) found that dogs trained once a week completed a specifically trained exercise in fewer training sessions than dogs trained 5 days a week. When we look at the actual training sessions, dogs trained 5 days a week took an average of 9 sessions to learn the task and dogs trained only once a week took on average only 6.7 sessions to learn the task." (scentdogsaustralia.com)
Demant (2011) found that the optimal number of training sessions is 1-2 per week. Shorter duration of training is better than longer and dogs can remember a learned task for at least 4 weeks without having further training (this was as long as they measured but I would think it is much more). This means that breaks in training for vacation or busy schedules will not interfere with the dog's ability to remember past training. "
So, train smarter, not harder! It is essential to leave your dog some time do rest and recover from the training, but also to be consistent. The mix of those can be a good formula for success.