Question — Once I get fillers, do I have to keep getting them?

I've noticed a lot of people around me getting fillers lately, so I've become interested, but there is one thing I'm hesitant about. I've heard that once you get fillers, you have to keep getting them periodically, so I can't easily make a decision.

I heard that it is naturally absorbed over time, but I am worried that as it fades, it might actually look sunken or look worse than before.

I also heard that the duration of the effects varies depending on the area, so I am curious about the usual interval between treatments.

Since this is my first time, I'm worried about potential side effects or an unnatural look. I would be really grateful if those who have actually received this treatment could share their experiences or advice in detail on how to maintain a natural appearance.