Any professional job requires further education while yo are working. Whether you are a teacher, a lawyer, a software developer. Often, you need it to just keep up with recent developments. During Rema times, some would just read Galen (and, according to a story, Vilna Gaon rejected an eye doctor like that). In our time, there is so much new, and also you will want to check your own experience against knowledge of others.
Some can do it on their own, others go take classes. Just make sure, you are not wasting money and time and that you are doing your job honestly, that is to the best of your abilities. Not my words. I once attended a talk from a Rov, who also worked as a professional. Students asked him all kind of questions that they could not ask “learning Rovs” – how do you keep kashrus, take off yomim tovim, etc. He started with “before I answer your questions, I want you to know the first halakha – you owe 8 honest hours of work to your employer”. (this includes halochos like you can not take a night job if you will be tired at your main job).