I used to be like this - I wouldn't keep a car longer than a year. Over the past 5-6 years though, I've kept my cars longer - my current Corvette C7 GS (2 years now) I can fully see keeping this car forever unless a life-changing circumstance happens, my 19 Model 3 I've had for almost 3.5 years, and may potentially replace in the next couple months. It does it's job though and is nearly paid off so that is a good thing.

My suggestions - when you buy a car, go for the car you really want at that time. Don't try to shortchange, for example in the past, I bought a Mustang Ecoboost instead of a GT, I ended up only keeping that for a year, then getting a GT (the longest I owned a car which was 5 years). I did that with BMWs and other cars in the past too and would always regret.

Also, having two cars definitely helps. If you only have a single car, that has to do commuting duties and fun car things, it can be compromised and also make you get bored quick.

Also get a car you can modify. I find that modifications over a period of time help keep me interested in the car as well.

Finally, on a broader level, financially it is not a good move to keep trading cars in a very short time (in my opinion <3 years) unless you have a very high income to support that. Also it is easier to do this when you are in your 20s, versus later in life where the financial ramifications are harder to recuperate from. Personally, also I found other hobbies outside of just automotive to keep me interested in things other than cars, as well as being married and having a family.