Hello, good to have you here at the community. If you would like to publish a new application for public use, you should run the droplet 24/7. Else if you would like to test things, and trying to make some new things working you could put the droplet online sometimes. Even though if you keep it offline, you will still have to pay for the space thats being hold for your droplet. So best thing to do in my opinion is just to keep it online 24/7