which of these two timers is more resource efficient?

Timer 1:

float timeCount = 10;

void Update()
{
  timeCount -= Time.deltaTime;
  guiText.text = timeCount.ToString("F0");

  if (timeCount > 0)
  {
    guiText.text = timeCount.ToString("F0");
  } 
  else 
  {
      Debug.Log("Time is up.");
      guiText.text = "Time's up.";
  }
 }

Timer 2:

int timeCount = 10;

void Start()
{
    InvokeRepeating("Timer",1,1);
}

void Timer()
{
    timeCount--;
    guiText.text = timeCount.ToString();

    if(timeCount < 1)
    {
        CancelInvoke("Timer");
        Debug.Log("Time is up.");
        guiText.text = "Time's up.";
    }

}

Timer 2

Reasoning: The resolution on timer 2 is much more coarse, it only updates the guiText once per second, as opposed to every frame.

I would choose option two mainly for the reason that it makes your code look cleaner. Performance-wise you wouldn’t notice any difference. Also performance optimisation requires that you do benchmarks and you shouldn’t waste any time on it early in development.

Hope you find my answer just as good as I had planned it to beeee (I’m awsum)