You can apply unless you have remarried and were either the respondent in the divorce or a petitioner who did not make financial claims in the divorce petition.
Whether you need to get closure by way of a financial order depends on many things. For instance, if your ex was the respondent in the divorce or was the petitioner who did not make any financial claims in the divorce petition and you know your ex is soon about to remarry then you may need to do nothing. It very much depends upon individual circumstances.
