By when should I take the PECB exam? (e.g. deadline of the first attempt)

Within 1 year, technically if you are happy with your PECB Exam preparation, you can book PECB Exam, as soon as you receive Coupon code from PECB. SMATICA recommends its students to book PECB Exam 1^st attempts at least 90 days, before coupon expiry, so that they have sufficient time to book free PECB Exam retake.