Accepting an answer is entirely your personal choice as the OP. You can do it at the first opportunity, wait a few days/weeks/years, or never accept at all. When an answer is accepted, this simply indicates that the OP found it to be the best answer to their question.
But, your question is not just for you, but for the whole community and all visitors to our site, for as long as it lives. Therefore, if the question remains open, new answers may be added at any time, and the accepted answer (the one the OP found most helpful) may not be the most highly upvoted. Network-wide, there are many questions where the accepted answer is less highly upvoted than one or more other answers.
It's worth noting that you can also unaccept and accept a different answer at any time.
Accepting an answer does not close a question, and has no effect on it other than marking it as solved for the OP. I would strongly encourage anyone who can provide an answer to a question to do so if they can offer a different perspective or approach; do not be put off by the fact that an answer has already been accepted. We are here to help each other and visitors by sharing knowledge widely. If you can contribute, do it!