Short answer: if you're asking, free is probably enough — for now.
The free tier gives you limited access to the good models. It gets throttled at busy times and caps how much you can use the best features, but for questions, drafts, and learning, it's genuinely usable.
Pay when one of these becomes true: you hit the limits during actual work (not play), you're using files, images, or voice daily, or you'd feel it if access disappeared for a day. That last one is the real test of whether a subscription is worth €23/month.
One wrinkle: if your main use is writing, try Claude's free tier before paying for ChatGPT — many writers prefer it. Confused about which? That's literally what our quiz is for.