There’s no duration for when you’re counted out of the labor force; only when you stop looking for work. Your incentivized to report your looking for work (and provide proof) to get unemployment benefits, and those who opt out of such benefits for more than 4 weeks are not counted as part of the labor force.

I think that’s fair, since even if you are homeless, as long you’re receiving unemployment benefits, you count as part of the statistic.

And there’s good reason to count certain people out of the labor force. Retired folks, stay-at-home parents, anybody else that’s willfully unemployed—if your working in or around government trying to make labor policy decisions, including these people gives you an inaccurate picture of the labor market. If you want to help people get jobs, you need to focus on the people that actually need help.

Of course no statistic is perfect, but broadly, I think that the unemployment rate is a useful and accurate measure. If you think otherwise, I’d invite you to propose a good alternative.