Time.frameCount  

// Makes sure that RecalculateValue only performs
// some operations once per frame and no more.
static private var lastRecalculation = -1;
static function RecalculateValue () {
    if (lastRecalculation == Time.frameCount)
        return;
    ProcessData.AndDoSomeCalculations();
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    private static int lastRecalculation = -1;
    static void RecalculateValue() {
        if (lastRecalculation == Time.frameCount)
            return;
        
        ProcessData.AndDoSomeCalculations();
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    private static lastRecalculation as int = (-1)

    static def RecalculateValue():
        if lastRecalculation == Time.frameCount:
            return
        ProcessData.AndDoSomeCalculations()