When do you know "Now is the time to switch!!" ?

You mean when is the right time to change job or career?

When it’s not going according to plan or expectation, with no perspective of changing this while staying where I am now. Generally speaking, a job must be self-fulfilling to me in terms of:

1. Professional and personal growth opportunities.
2. Recognition
3. Passion

Remember that career change doesn’t have to mean you risk everything. You can repurpose your skills and talents, and make a smaller shift in a direction that will allow you to do more of what you love, while still making the money you need to, to fulfill your needs and wants.

1. You are chronically worn out, exhausted and depleted.

2. The skills, responsibilities and tasks you are focused on are not you at all.

3. You have the irrepressible feeling that your talents and abilities could/should be used in a totally different (more creative and impactful) way.

4. Low salary

5. No growth opportunity

6. Lack of respect

When the one got a slap on the face, it's time to change everything and your attitude to save yourself.

When the company treats you like dirt when you should be treated like a king.

When the passion dies or there is no work recognition, growth or respect, better make a switch.