The people who know me, know that i have a big collection of scale model cars. 
I got interrested in collecting when i bought a scale model car for my ex- father-in-law. He got the Jenson Button 1:18 Williams car if i recall correctly. Although JB wasn’t an hous hold name in F1 at that moment, years later he became world champion.
But in that shop i saw a 1:18 scale model of the Arrows F1 car of Jos Verstappen. At that moment Jos was the most succefull driver from the Netherlands we had. (Eventually his son, Max, became the number one dutch driver).
I really (and still do) Â liked the color schema: Orange and Black. The detail is still great and if you place one in a display, it pops.
Eventually got about 15 1:18 scale model cars. The problem with this scale is that they are relatively large (for a scale model)! :D. Here is a picture of the different scale sizes:
Left to right: 1:64, 1:43, 1:32, 1:18
As you can see the scale difference is pretty large between 1:43 and 1:18. Those 2 scales are the standard in scale model collection btw. A lot of collectors are using a (now defunct) Ikea Bertby case. The main “problem” is that a 1:18 car takes about 1 shelf, while if you collect 1:43, in worst case, you can place 6 on 1 shelf.
Eventually i mainly started collecting 1:43, because i could place more on 1 shelf, and there was more variations in cars. The problem is that there are so many different race classes and race drivers that the main stream F1 watchers (no offence btw) don’t know of. And even in those lower race classes there is even a gradation between the top teams (Porsche, Audi and Toyota) and the lesser gods like Murphy Prototypes. So people also don’t want to spend a lot of cash on all the cars.
At first my collection would be only about dutch drivers and/or dutch teams (aka: “It isn’t mutch if it’s not dutch. “). Now i’ve shifted to a more “If i like it, i buy it.”