Catch 22

Most people do not start looking for a new job until they are sick of, and demotivated with, their existing job. The problem with this is that they get so demotivated, that they also lose the energy to actually put effort into finding a new one, which leads to further demotivation. This seems to loop around until they get to the point where they simply cannot stand to remain, and quit in disgust. If lucky, they will find a good replacement job, if unlucky they will take whatever they can get (or remain unemployed).

(The same seems to apply for being unemployed - you are not motivated because you are unemployed, and are unemployed because you're not motivated)

The trick to staying motivated seems to be identifying the potential within your current job - and therefore if it is going to be long term or temporary. If you can recognise that you will not stay with that job for long, then you can start looking for a new job before you get demotivated. Then you will be able to spend the extra time looking for a potential long term job.

Avoid catch-22 situations, rather than trying to escape from them.