It depends on your English level really, and the band score you need. If it's very good, you'll likely be fine.
However, usually it's a good idea to get feedback on writing and speaking from someone who knows the test criteria well. You can post writing and speaking here but usually you will get comments from people who don't know the IELTS requirements. For example, they'll correct the grammar and vocabulary mistakes in your writing, but will say nothing about task response and cohesion and coherence. Also, very often, the grammar and vocabulary corrections focus only on accuracy. You don't get comments that improve the range. The usefulness of correction here is very limited for exams with specific marking criteria.
Good luck in the test!