IF you are adding more resources to your resource thread you can make a duplicate post sooner than the typical 72 hour limitation. However, this should be avoided whenever reasonable and should happen no more often than once in a 24 hour period. If you say something and 12 hours later you make something and want to show it off in a new post, that's fine, I'm not going to bother you. If it's 2 minutes after your last post and you just want to say "new stuff in first post" then just edit your last post. If you've already done an update post, please don't do it again until 24 hours has passed. You can always update your first post as often as you like.
This is an exception so that artists who have recently answered support questions don't have to wait a long time before letting people know they have new content. If you abuse it to post one thing every day so that your thread stays on top, I will get annoyed.