You need to know some rules. Rule 1 no posting twice or more in a row. You have to wait for somebody else to post before posting. Rule 2 no bumping threads.
1. It depends on the situation,
it's not always bad to double post, for example when there's some time in between the posts more than a few hours and you have something to add
2. It depends on the situation,
it's not always bad to bump topics, making a useful and relevant reply to the topic is usually fine and honestly all the follow-ups that only tell people not to bump are much more annoying