There is no single number that fits everyone, but there is a right answer for you, and working it out is simpler than you might think.

Skin check frequency is a risk calculation, and everyone's risk is different. A fair skinned roofer with a family history of melanoma and a fresh crop of new moles is not on the same schedule as an olive skinned office worker with three freckles. Any website that hands you one universal interval is guessing. What a doctor does instead is examine your skin, take your history, and set an interval that matches your actual risk.
The more of those apply to you, the shorter your sensible interval gets. Living in Queensland already puts everyone a notch higher than the national baseline, because our UV is relentless. It is a big part of why 2 in 3 Australians will be diagnosed with skin cancer by age 70.
You book a full body skin check. At the end of it, your doctor tells you when to come back, based on what they saw and your history. For many Queensland adults that ends up being roughly yearly, for higher risk people more often, and for some people less. The point is that the number comes from an examination of your skin, not a website average.
First, look over your own skin every few months, using the ABCDE guide as a prompt. Second, and more important: a new spot, a changing spot, or a sore that will not heal gets booked in when you notice it. The schedule is for skin that looks fine. Changes jump the queue, always.
Then the right time for your first full body check is now, whatever your risk level, because it gives you and your doctor a baseline to compare everything against. It takes 15 to 30 minutes and you do not need a referral.
This article is general information, not medical advice. Your own doctor is the right person to set your skin check schedule.
Book a full body skin check and leave knowing exactly when your next one should be.