FE model: sufficient number of transitions?

Hi all,

I am just wondering if there is a way or a rule of thumb on how many transitions I need to observe in order to run a FE model?

I am looking at transitions out of cohabitation and am observing 69 transitions. I would like to run a FE model with a continuous variable (income) as my dependent variable and my main independent variable Cohabitation_Separated (0 if person is cohabiting and 1 if person is separated from cohabitation). I don't intend on including too many control variables (maybe around 5 variables).

Are there any power tests I should run or any other test I should do to make sure that 69 is a sufficient number?

Thanks,
Nicole