Like the saying goes Throw mud at a wall and eventually some of it might stick. You wouldn't approach your teaching this way or expect your students to have to learn this way so the same goes for your units of learning. There is no quick way to answer the question so here is the long version.
First lets look at the fundamentals of a building a unit of learning - the starting point;
It is usually over a period of time such as August to October mid-term (9 weeks), November to Christmas (7 weeks) or January to February mid-term (5 weeks).
It will have more than one learning outcome (usually)
What is the knowledge, understanding capabilities and skills we want our students to have acquired at the end of this unit
It is collaborative meaning more than one person in the department will have helped construct the unit
Let's look at where you do not start when building a unit of learning;
Chapter in a book
Great set of PowerPoint's, YouTube videos or other learning resources we have in a folder
How much can we fit in during that period of time (consideration not cramming)
So when it comes to answering the question - how many learning outcomes should I use in my unit of learning? There is no right or wrong answer only a guiding rule. Here are some considerations;
If I have 45 learning outcomes in my subject and using the logic above if I have five units of learning for each year that is 5 units x 3 years = 15 units of learning. So 45 outcomes / 15 units = 3 outcomes per unit. Great I have used all my learning outcomes? This logic is not true.
All subjects are different from literary to languages to technical so do the same rules apply? No.
Some terms are 9 weeks while others are only 5 weeks, do I still have one unit per term? Your department must collaboratively decide on this.
Take-away
Remember - students will not truly attain the knowledge, understanding, skills or values of each outcome until the end of the Junior Cycle three years. Some outcomes are simple while others are complex, some are short while others are detailed (read our article on what is key learning for more on this). You are expected to use some outcomes more than once over the three years in your units.
Don't start with the content - that is not what its about. What do we want students to know or be able to do over the course of the unit (block of time) and start there. If you want to start with the name of your units first then develop themes such as Being a consumer, Entrepreneurship, or Household Expenditure which will shape the basis of the learning outcomes that you will choose.
Since every subject is different some might have five units over the course of the year, some might have two in the first term, one in the second... you have the freedom to decide.
Develop realistic, achievable outcomes for both you and your students.