Execution for Every x Seconds

It's quite common to execute functions for every period of time. 
And the following is the method I mostly used:

void Start () {
  nextTime = Time.time;  
  interval = 1; // every single second
}

void Update () {
  if (Time.time > nextTime) {
    nextTime += interval;
    // do things here
  }
}

Especially, notice the difference of initialization of nextTime

// this would fail when you reload the scene. 
nextTime = 0; 

// this would execute in the beginning
nextTime = Time.time; 

// this would execute after an interval
nextTime = Time.time + interval;