I think for some of us it's the never ending quest to find "the perfect soap" or "the best razor ever", for others it's the enjoyment of getting a new soap and enjoying another scent, etc.But I've been there many times, and yet I end up buying more .... When I really got into straight razors some four years ago, I thought I would retire my DE collection entirely. Yet I got back to DE shaving. I thought I had all the razors I needed, yet just this summer I got four new razors, and having a fifth on it's way. This is way beyond "needs" ...!! This is beyond any conception of "rational". I can't explain what's going on, it just happens. Yes, I am slightly worried, but it's also a very enjoyable ride.
I do know this...the makers of all things wet shaving would starve if everyone bought just one DE razor and one soap