The idea that closure looks or feels exactly the same for different people is erroneous, and indeed a block towards achieving closure. For some, it means a literal ending that involves removing or disregarding something. For others, closure might involve an intellectual evolution to the final point, a dot point summary and conclusion. It could be an emotional transition, a relinquishing of an existing relationship which allows space to be created for something new. Closure, in a positive context, presumes that there is a transition of energy, from being more demanding to less demanding, moving away from something that is controlling you to a place or state that gives you freedom.
Closure, across all of these spectrums, is about moving on. But - you can still move on and have no closure. You can move on with life and get a new job and move cities and cut your hair, and that's doing something new, something different - but if you're still emotionally engaged with the house you just left, have you really achieved closure?
Perhaps it's best to consider closure as a graded phenomenon- that there are grades such as 'physical', 'intellectual' and 'emotional' - the latter being the most challenging to achieve. For most of us, emotional closure doesn't occur until the others have happened - and rarely do all three happen at the same time. Often, we can substitute closure for mere replacement; sometimes, replacement with a better option can lead you to a place where you no longer desire the problematic thing. But, if the replacement doesn't become a solution, if it leaves you in the same state, or even somewhere worse, it can prolong the sense or lack of closure.
Closure often requires using words and reflection, as well as "actions". Ultimately, it's the belief that the previous circumstance, state of being or option has no further value to you, that determines whether you have closure or not. In other words, you have all the information you need to make the decision and you have decided, at both an emotional and intellectual level, that you no longer choose it. You know when this realisation is real- because you don't have to tell yourself anymore. Instead your behaviours prove that closure has occurred. In the meantime, you may find that your actions (or subconscious) contradict what you are trying to tell yourself. And that's okay. It's part of the process of truly achieving closure.
Another misconception about closure is that it should feel "GOOD". Closure isn't always going to make you happy at the time, it just takes less energy. It’s a change of an emotional or physical state, and it uses up less of your resources. Being distressed is more energy than being sad, being angry is more than being resigned. Release, as opposed to relief. Closure is sometimes acknolwedged only when people feel ‘better’, and the problem is that sometimes we continue engaging with the thing until we do feel better… but feeling better often comes later.
Searching for elusive happiness, (which is often just relative relief from negative feelings), might actually end up re-opening wounds. For example - if you break up with someone, you may feel you understand why you did it, and that there’s no other way forward: you have gathered all the information you need, and truly believe that there is no longer a useful relationship, but, then, that makes you sad. If you think closure requires you feeling happy about the end of the relationship, you may continue returning to that person to find that proof that you are glad it's over, and end up prolonging that relationship. You may have renamed it in your head, but it is really just re-dressed in a new costume, and underneath it is essentially the same relationship. You haven't moved forward. Maybe there's a good reason, if you keep going back to get closure, and it's not working. You may need something else - a different emotional response, a new piece of information. But you need to know that, to look for it, rather than thinking you're fine, and just expecting to be happy. The blinkers you put on will stop you finding what you need to actually see past the problem.
So, to have closure - you need to start something new. To transition from one state into the next, you need reflection, rest and to reset. It's about identifying the things that have made you feel good, the things that made you feel bad, and above all, the changes that are valuable to you and your future, regardless of how they might make you feel now, in this moment. And, once you've closed something, you need to have a period of time where your heart and mind don't need to engage with anything related to what you're closing. You need time to forget, recuperate. Reseting is about looking outwards, forwards, and seeing what's going to happen next, understanding why you might forge forward on a new path. You’ve acknowledged it, how it’s changed you, now you need to let that go and think about the new you, with all the changes incorporated- how does the new version of you integrate into the world and "start again".
Closure is one sided. Closure is your experience. It’s up to you. When and how it happens for you is independent of the other person. The same experiences and information will create closure for some and not others - and peoples' needs and perspectives are different. Only you can control your perspective on what you’re trying to close, and how much time and energy you will dedicate to the process.