When should I book my test?
Do not book your test until you are consistently getting the scores you need in practice. To clarify this, if you need all Band 7 scores, make sure that you are consistently getting Band 7.0-7.5 scores in all 4 skills. That way, you’ll be sure that even on a bad day, you’ll still likely get your score, but on a good day, you might do even better than necessary.
Never gamble that you’re ready. BE SURE.
Here is some more help with how to know if you are ready to book your test.