I had a small layout my dad built me as a child. To be honest I can not remember what train set I had. And also remember very little of the other details. So I will consider my starting point as 2011, when I got back into the hobby.
I still do not have a permanent layout, but I am happy with most of the purchases I have made so far. I'm using Atlas track and switches and am very happy with them, as well as DCS and mostly MTH trains. I ordered a Legacy system last fall when I purchased my first Legacy engine (I'm sure you all know how that's going, hoping to get it soon and looking forward to it).
I started out with Railking stuff and then Premier. As for do overs, might have gotten a few less Railking items and a few more Premier, but overall I'm really happy with all my train items so far. I have had very few problems.
I was reading OGR magazines and also the other one for a while before I got going. Luckily, I found this forum early on. I owe a lot to all the contributors here for supplying me with the information I needed to take the correct paths for a lot of this stuff. One of the first things I learned was to pick one or two read names and stick with them. I have done that for the most part, cheating only a couple of times so far. Thanks to you all here on the forum I have made wise purchases (or at least I think so anyway) and am quite pleased so far.
The only thing I am struggling with is my layout planning. I want a larger one than I can afford all at once, so I've been trying to break it down into smaller sections that I can do a little at a time. So far I can't seem to come up with something I really like. I am going to use Mianne bench work, so I am just about to order a 6' x 16' set and put some track down and see how I like things and what I want to change. By the time I get that figured out, maybe I will have a better idea of what I want and be able to add on and some more layout area.
Surely something will come up that I will regret and want to redo someday. I'm sure that happens to all of us at one time or another. But so far, so good!