If you’re serious about your writing – and I mean any writing that is going to be seen by someone other than yourself – you should also be serious about getting your grammar right. This is the case even if you are of those who thinks grammar is overrated, that it’s ‘getting the meaning’ that matters. Remember that a good proportion of your readers will baulk at any grammatical error and will quite possibly lose focus on what you’re saying after they come across one.
In any case, good writing is professional writing. If you want to present yourself as someone who knows their stuff, you need to be able to write about that stuff in proper English.
So, next time you are wondering about the rights and wrongs of semicolons or dashes, where should you go for help?