If I am to carry out a survey on this topic I believe many will say NO and disagree that there isn't any need to apologize to your Ex after breakup or after a long time since you both are no more together,but I’m going to buck the trend and say that, YES, if you’re doing it for the right reasons, you should apologize to an ex,even if many years have passed.
Am going to do justice to state why some might think isn't necessary to apologize and why I think you should apologize:

YOU MIGHT BE OPENING AN OLD WOUND.
Some might think/believe if I apologize I am only opening an old wound, but I doubt it. If what you did hurt someone, my guess is if they still harbor bad feelings about what you did, the wound never truly closed anyway and in anothér sense you might open an ‘old’ wound, there’s also a chance you’ll end up healing an old wound, and your apology may well be what the wronged party needs. Many times when you hurt someone, what they really want is for you to acknowledge the pain caused; when you fail to do that, chances are you’ve caused damage to that person. What you’ve said in the past is, “you’re pain doesn’t exist, I didn’t see why I should say sorry.” By letting that person see you are sorry and that you have also suffered at the hands of your own actions, you are telling them they were not alone in their pain.


MAYBE THE EX DOESN’T CARE ANYMORE AND HAVE MOVED ON.
To some degree this is true,In most case most sane people, even if they have moved on, will still appreciate your effort. As long as your apology isn’t a veiled excuse to try get them back, and you’re careful not to make it sound like you’re doing them a huge favor by saying sorry. In this case it might seem like a redundant apology, but you’re not likely to bruise your ego too much.some how you might not know what’s going on in another persons heart, they might want your apology, just as much as you want to give it.Ee

IT’S BEEN A LONG TIME, WHY BOTHER?
Some many a time you could be the reason for the breakup and it’s still bothering you, and maybe it’s still bothering them. What does time have to do with it if there’s a chance you can put things right? I say take the chance, it’s never too late to offer peace and the world needs more of it.


THEY MIGHT TAKE IT AS AN INVITATION TO COME BACK INTO YOUR LIFE
If you’re going to apologize, go to the effort of making your boundaries clear. Even if you would like this person back in your life, an apology is not the time to do it. Apart from setting boundaries, if they do see your apology as a way back in, to which you’re not comfortable; I suggest using your ability and newfound maturity to let them down gently. Make it clear you’re saying sorry without expecting anything of it, and try to distinguish between them wanting back in, versus them wanting some answers. Your apology may instigate some lingering questions, answer them and let the other party have their closure too. An apology isn’t about you unleashing the words ‘I’m sorry’, and wiping your hands clean of the situation.

FEAR OF LOOKING PATHETIC AND THEY MIGHT REACT BADLY.
See gbege ooo!!! Who cares? You did something crappy to another human being, you can afford to lose a little face over it. Chances are they had their ego dented more than you did. At the end of the day you cannot control their reaction, just as much as they couldn’t control yours when you were set on hurting their feelings. If they react badly or call you names, or even worse, ignore your apology altogether; that’s the price you pay for hurting another person. An apology isn’t supposed to be easy, it’s not about you, and you’re getting a pretty fair trade.


THE BUT I WASN’T THE ONLY GUILTY PARTY SYNDROME
Have this at the back of your mind that each day you grow older and not younger,you no more the kid you were some years back,the earlier you stop point accusing finger and stop finding faults the better. I once dated a girl who I would say was a runs girl or do I say serial cheater,even though I was the wrong party who was emotional abusive,I still had to apologize for what I did and the ways I acted out. I had every right to argue her behavior was the reason for my inflicting pain, but ultimately I’m a grown young man with prospects and I’m the one responsible for how I act. Although I said sorry and I never got an apology back, but it did help me to close the door on a bad relationship.

NOTE:
An apology has nothing to do with you and everything to do with the person you hurt. Yes, you might lose some guilt from doing it, but that is not the point. Some times many may give you reason not to apologize,you know what? so many apologies are done incorrectly and for weak reasons. When giving an apology you should not expect to be forgiven. There’s a chance that what you did hurt your ex bad enough that they are not at a place to give forgiveness. Or maybe life hasn’t given them an opportunity to heal in the same way you have and they can’t find it in their heart to forgive you. That is their prerogative and chances are the hurt you caused is greater than the guilt you feel. But you never know. Saying sorry could be a big step in them finding their healing. Never give excuses for why you did what you did. No one cares why, even if they are the ones asking. The main point is you’ve grown and you’re owning up to it, in the end your words mean little if your actions don’t reflect what you say. If you claim to have learnt your lessons, be sure that your behavor in life correlates to that and you are not just repeating old mistakes. Otherwise it’s better your apology is left unsaid.

Yes

some dier pride nd ego..would neva let dem apologise...

You could tender your unreserved apologies anytime you come to realise your mistakes. It doesn't matter how long it took you to say it, what matters is if you said it at all.

Basildvalour:
You could tender your unreserved apologies anytime you come to realise your mistakes. It doesn't matter how long it took you to say it, what matters is if you said it at all.

yeah u right but most people just fail to realize they are wrong even when they are

?

Chizzy20:
some dier pride nd ego..would neva let dem apologise...

yeah you right that's where maturity comes into play....

the keystone to a great apology is to stick to apologizing for what YOU did. To me I feel is best one Makes a list of what one has done wrong or failed to do, under each of these list how you believe the other person was likely made to feel

Sure,apologise and stay on your lane. But most guys only apologise so as to be given the chance to do the deed again. I pity the gullible ones

MizTyna:
Sure,apologise and stay on your lane. But most guys only apologise so as to be given the chance to do the deed again. I pity the gullible ones

to me my dear I still see nothing wrong in going back to any Ex,it could be that things didn't work out then doesn't mean it wouldn't work out in the future. There are cases where people break up and make up after some years apart. Sometimes the time away avails you the opportunity to appreciate that which you once had and never/failed to appreciate. Where most people get it wrong is tryna come back during the course of apologizing