Punctuation is very important in the IELTS test. First of all, in the writing test, you'll need to have good accuracy with your punctuation, including things like apostrophes, full stops, commas and also in the listening test and reading tests it's important to transcribe the data correctly. For example, how we separate 1000. We would use a comma, but in some languages people use a full stop or a point. This would be marked as incorrect. So please be very careful with your punctuation.