For job hunting deduct- Define break between your past job and looking for a new one - what is the acceptable amount of time ?

This is clarification of the previous request.  If you are unemployed, the type of work you did for your past employer is your occupation. If there is a substantial break between your past job and looking for a new one, you cannot deduct your expenses. 

Define substantial break between jobs?  If the individual was last employed in 2015 and has been looking for a job in his last substantial employment; is substantial break defined as 1 month, 6 months, 1 year, 2 years?  In other words "What is the maximum amount of time whereby the individual is allowed to take their job hunting/search/interviewing, etc. expenses?