I think it depends on what you want to do with your English. Personally I don't study it regularly. It's not because I am very good at it but it is sufficient for me. Watching movies and reading some articles time to time help me not to forget it too fast.
I don't know your level, however you are at the right place for sure :) You can improve your speaking and listening skills here. To improve your reading, I suggest you to read articles in which you are interested. For instance you can find some websites related to your hobbies and follow them, so that studying wont be too boring :)