If you're learning a language, is it worth your while to go to language classes, or is it better to study on your own?
Language classes offer you opportunities to practise using your language with others, to get answers to your questions, and to meet other learners. They also give a structure to your studies, which some people prefer. However students are rarely at exactly the same level and each will probably have different expectations from the class, and the teaching style and methods may not suit you.
Studying a language on your own gives you the chance to study what you're interested in at your own pace and in your own way. On the other hand if you're studying on your own you have to be disciplined and motivated in order to study regularly, and you probably won't have people to practise with and to answer your questions.
Many people go to classes for an hour or two a week and don't do much else to learn their languages. Then they wonder why they aren't make as much progress as they hoped to. I think classes should be seen as a useful part of your learning strategy, but not the sole part. To make good progress in your studies, you need to study every day, even if it's only for 10 or 15 mintues, and to immerse yourself as much as possible in the language by listening to it, speaking to yourself and anyone else who will stay still long enough, reading it and writing it.