I'll weigh in with from the "novice" point of view. In the past I had tried to use some garbage hand planes I came through unremembered provenance, with no success whatsoever. That said, I never bought a book, never asked advice and, as this was pre-youtube, never sought online instruction. I set them aside and didn't look at them for nearly 2 decades.
Last year, I got interested again and dusted off those planes. Turns out they were absolute garbage. The cap irons were just shaped stamped steel as were the blade adjuster knobs. No amount of tutorials could make these things work as intended. Then, maybe a couple months after that, I was in a junk shop and they had a Stanley #4, a Fulton #5 equivalent and a little Stanley block plane, all for $6 each. They were all kind of rusty, but for $18 I figured what the heck. I brought them home and refurbished them as best I could according to the Paul Sellers instructions referenced in an earlier post. Both the jack planes had cracked totes. I repaired them with epoxy and they've held up fine since then. I was fortunate that all three had flat soles with no cracks or major blemishes under the rust. One of the irons was nicked but I ground it down on a belt sander and re-beveled and squared the edge. Once the irons were sufficiently sharp, all three worked very well, the Fulton less so than the others.
In my NOVICE opinion, you can learn a lot by finding some cheap rusted gems at junk shops, flea markets and the like. Watch the Paul Sellers video or buy a book if you prefer. Disassemble them, and acquaint yourself with how they work. Sharpen the irons!!! No matter how well you restore a plane, you'll quickly get frustrated if you don't sharpen your blades adequately.
And as to whether this qualifies as an addiction…well, I have 2 Stanley #4s, one of which I converted to scrub plane (another great Paul Sellers video), 2 #5s, one the aforementioned Fulton and a more recent-and far superior-Stanley model, a Stanley #3 with a corrugated sole which I absolutely love, a Stanley #78, and a couple little block planes, one a Stanley, one a Buck Brothers. For all of these I paid less than $150 total. They took a lot of elbow grease to restore and sharpen, but they work just fine.
I have come to a great appreciation for hand woodworking as a result. It's meditative for me. I would recommend to ANY woodworker to at least acquaint themselves with the basics of hand planing even if you don't plan on using the method extensively.