I agree with Intruder and RAT 5: understand what the automation does and why and you can make an informed decision about what modes to use in a particular circumstance.
*Think* about what you want to achieve and how environmental factors (speed, altitude, available performance, ATC, other aircraft, etc.) are going to affect you then make a choice.
There are often many ways of achieving similar results and the aircraft manufacturer has acknowledged this by giving you options. Don’t be a microwave operative - be a chef!