Whether to accept an answer or not is entirely your personal decision and it has nothing to do with encouraging people to contribute answers. Even if an answer is accepted, a new user can write an additional answer.
If you think that a new answer is more helpful than the previously accepted one, you can change the acceptance by clicking on the acceptance tick of a new answer.
But, please make sure you accept an answer that solves your problem with the right reference and examples. If there is not a helpful answer, you don't have to accept any answer.
Related question on Meta Stack Exchange:
How long should/can I wait before accepting an answer?
How does accepting an answer work?