It can work, but there's no guarantee how many of your subscribers will stick around, and how long you'll retain your €1000 monthly income. If you fall below €1000 because some subscribers cancel, then your last goal and progress bar will again be displayed on your campaign page. But experience shows that interest in a campaign
and its goal
is time-limited. That's why it can help to set a new goal from time to time. That doesn't require as much work as launching a new project from the start. You don't have to start all over again to set a new goal. Goals help you to make each step of your work transparent and to win new subscribers. Put another way, it helps you ask for money.