You're not the only one LOL
That is the way we were all told to do it years ago. There was no such thing as internet when I first started keeping fish (showing my age LOL) to get advice from any other fishkeepers. We just assumed those in the aquatic centres were experts and did exactly as we were told.
I knew nothing about doing weekly water changes either. I used to wait until the water looked quite yellow!!! How my fish survived I don't know. I cringe when I think back to those times of being totally naieve about it all. I even have some old photos of my early tanks and it's quite shameful to see how disgustingly dirty the water looked compared to how I keep my tanks these days.
My boyfriend keeps asking me why I am wasting so much time every weekend doing water changes when he "kept pirahnas for years and didn't do any water changes" GASP!!
Ah well, you live and learn (well, hopefully)!
When you set up your tank, how often were you doing your water changes? Could be that if you were doing regular changes and had a good filter and not overstocked, live plants etc you completed a successful fish-in cycle (successful in the sense that your fish didn't suffer illness or death).
Athena