Please, don't vote (like) other people posts or comments that are 7 days old or older, because NOBODY would have any benefit of it. Posts are active only first 6 days and 12 hours. After that, no matter who votes and with how big votes, nobody would earn anything.
But if you vote for posts and comments that are posted in the last 6 days, both parties would benefit from that (you as a curator, and the publisher of the post as the author).
Otherwise, you would only drain your voting power and resource credits that might end up that you wouldn't be able to do anything on the network.
I see that you are new here, therefore it would be wise if you learn first how things work on this network.
I would suggest you to start from Hive's FAQ, especially the part about voting and curating, starting with the answer on the question "What is my voting mana?"