As far as I know, almost everybody here has a regular job in addition to YouTube. You must take care of the job that is paying the bills first but with all of your spare time, you should be focusing on growing your channel. That includes replying to comments on your videos, not just making new videos. Having your privacy settings to allow your posts to appear in your subscribers feeds is just as good as making videos and promoting them.
On the note of commenting, in your spare time, it is a good idea to watch similar channels and comment in their videos so that people become aware of you and might possibly come check out your channel. I'm no saying to post "come check out my channel". I'm saying to post some constructive commentary regarding their video so that people take notice of your comment.
That means during lunch and break, you are watching other videos and commenting, not just chatting with friends in the lunchroom.