Is the $1100 minimum unearned income allow per year or life time?

A student has no income, but have some investment with small gain.

Is the $1100 minimum unearned income allow per year or lifetime?

Suppose:

  • Year1:  investment gain $700.  sell and realize the gain.  no need to file/pay tax
  • Year2: re-invest money and gain $500.  sell and realize gain.  no need to file/pay tax
  • as oppose to do nothing in year1 and then year2 would sell gain 1200 which would require tax filing and taxes.

Is this correct assessment?