Preparing for a Cisco Certification solely with Practice exams is a method that many candidates follow, however I do not recommend this study method at all. My intention in this article is not to slam practice exams. I just want to address the phenomenon among Cisco certification candidates who use practice exams solely as an attempt to pass their exams with the least possible effort. Practice exams should be used in your study strategy as a complimentary option together with other study resources such as books, video trainings, practice labs etc. When you are in the field in front of a rack of routers and switches trying to implement a network design, there is no A, B, C, or D choice like the practice exams. You’ve got to know what you are doing.
The current Cisco certification exams are designed in such a way as to weed out those candidates who just memorized hundreds of possible exam questions in their attempt to pass the exam. If those candidates used only practice tests for preparation, they will just be disappointed on exam day. The certification exams will not only test if you possess the requited knowledge, but also if you have the ability to apply that knowledge in real world cases. Thats why the current Cisco exams are full of practical scenario questions. By taking one practice exam after the other will certainly not develop this skill.
Practice simulators are also fine up to a certain extent, but also do not depend very heavily on them. The most common network simulators I’ve seen do not let you make any mistakes on the router or switch configuration, so you do not actually learn from your mistakes. Remember that making mistakes on a Cisco configuration, observing them and then fixing them is what really helps to actually learn what you are doing.
When preparing for a Cisco Certification (especially for an entry level certification such as CCENT and CCNA) you are not just studying for an exam. Rather, you are building and fortifying your base and foundation for the upper layer certifications and for your career as well. Try to make your study efforts as effective as possible by building a solid foundation. You will achieve this by learning all possible networking theory and fundamental concepts, rather than memorizing hundreds of exam questions. Especially when studying for CCNA, the knowledge that you will acquire will be the most important from all and will be the corner stone for future certifications such as the CCNP and CCIE.
The best preparation for Cisco certifications is to stick to a well-rounded study plan which includes books, lab networking equipment (real or virtual) and practice exams. A recommended training package for Cisco certification exams is this computer based training here. If you combine it with a relative book from CiscoPress then you will have a complete well-rounded study package for passing your Cisco exam.