A while ago YouTube introduced the new Community feature. As far as I know it's only availible for channels with 10,000+ subs. You can make a poll, add pictures (like instagram) or add an existing video from your channel to the post. A few days ago I decided to make a community post with a video of mine that I uploaded 1,5 years ago. So not thinking much I released the post. And guess what happenend. Within 2 days the video got more views than it usually gets within a whole month. And it makes sense! All the mobile subscribers see the video in their live feed. So it gets a similar attention as if I would have just uploaded the video and my subscribers get notified about my new video. So especially in times where I don't have the capacity to upload new videos, I will simply add older videos to the comunity tab and my subscribers will still get my videos into their live feed. Of course this should only be done with videos that are already older. Otherwise people would not watch the video since they know the video anyways. But putting ones or twice a week a video into the community tab shouldn't hurt and will give a little boost to the video.