Free material teaches you the content; Premium makes you perform it under exam conditions. The two do different jobs, and the reason to add Premium is that no amount of reading rehearses the timed, one-commitment decision an IT or security exam actually scores.
Free resources are genuinely useful — vendor documentation, community notes, a borrowed study guide, a walkthrough video all build the knowledge a certification rests on. What they cannot do is put you under a clock with one commitment per item and an order you have never seen, then show you where your judgment slips. That gap is the whole reason Premium exists.
What Free Study Leaves Untested in IT Prep
Consider threat modeling. Reading about STRIDE, you can recite that it sorts threats into spoofing, tampering, repudiation, information disclosure, denial of service, and elevation of privilege. A Premium item makes you use it: here is a data-flow diagram with a client, an API gateway, and a database, one arrow labeled a certain way, and a question asking which STRIDE category an unauthenticated write on that arrow represents. Several categories look plausible; one fits the flow described. Recognizing the definition on a page and selecting the right category against a specific diagram while the clock runs are different acts, and only the second is what the exam marks.