def time_rounding(seconds, sig=3):
    """
    Function to round seconds to `sig` significant digits
    
    Parameters
    ----------
    seconds : float or int
    
    sig : int, optional
       number of significant digits
       
    Returns
    -------
    rounded_time : string
    """
    if seconds < 120:
        return ("%#.3g seconds" % seconds)
    else:
        minutes = seconds/60
        if minutes < 120:
            return ("{0} ({1}′{2}″)".format(
                "%#.3g minutes" % minutes,
                str(int(minutes // 1)),
                str(int(seconds % 60))
            ))
        else:
            hours = minutes/60
            return ("{0} ({1}′{2}″)".format(
                "%#.3g hours" % hours,
                str(format(int(minutes // 1), ",d")),
                str(int(seconds % 60))
            ))