when private constant?

is right private consistent following situation:

say i have diversion lives non-static startinglives variable. during start diversion i set lives non-static equal startinglives variable. i customarily it:

private var lives:int = 0;
private var startinglives:int = 3;

private duty startgame():void
{
   lives = startinglives;
}

(example formula actionscript btw)

my doubt - should unequivocally be:

private var lives:int = 0;
private const starting_lives:int = 3;

private duty startgame():void
{
  lives = starting_lives;
}

startinglives seems puzzled change during runtime, should i const, change behind non-static turns out constant?

update: settle seems good constant, nonetheless amdfan's idea competence wish bucket value config file?