My gear purchases mostly fall in one of two categories: (1) gear that gets purchased to fulfill a specific need or function; or (2) gear that gets purchased due to certain curiosity as to what the item does and how it functions. I would say 90% of my purchases fall within the first category. However, and as I will explain ahead, even gear bought on a whim can bring significant changes to your photography.
What, or how much, gear you need is very much dependent on the type of photography you engage in. I am, as most of you probably know, not a professional photographer, in the sense that I do not make my living from photography. I do, however, practice various different types of photography, some of which require certain gear. I do a fair amount of dance/performance art photography, which is made significantly easier by gear with extreme low light capability and robust autofocusing. I have been able to get away with cameras lacking in either or both functions (I successfully photographed several performances with a Leica M9P) but the experience is much less stressful, and the results generally better, with more capable gear.
One other area which I have engaged in of the last few years is landscape photography. Again, this requires some specific gear: a sturdy, easy to use tripod is a must. Sharp wide or ultra-wide lenses are essential, and ND and polarizing filters also come in handy.
Finally, I do enjoy portraiture and, specifically, studio photography. All of the portraits I posted in the April 2020 challenge were shot with studio lights (specifically a Profoto B2 system), even the ones shot outdoors. Speedlights (which is what I used before acquiring the Profoto system) are usable, but much less effective, and very limited in the light modifiers that may be used, and in the power they put out.
What I mean to say is that, were I to limit my kit to one body and three lenses, and no other accessories, it would significantly limit the photography I could do.
As to cameras, I have not had many system changes over the years. I photographed with a Canon system from the film days, and well into digital. The Leica bug bit me when I was looking for something much more compact (but with better performance than 2012 m4/3 performance, which was my compact system at the time), and the M9P, while limited in several aspects (high ISO performance, speed of use), together with Leica glass, was an image quality monster. I kept my Canon system for when autofocus was convenient and for use with flash.
The switch to Nikon came in 2015 with the purchase of the Nikon Df. This is a prime example of a piece of gear I bought simply because I was curious about it, and not to fulfill any particular need. As it turned out, the image quality of the Df was significantly superior to that of the Canon 7D MkII which I had at the time, particularly with regard to dynamic range and ISO performance. As I had started to build up a Nikon lens system, I sold my complete Canon system. At the same time, I traded in my Leica M9P for an M-P 240 under the Leica upgrade program for M9 cameras with defective sensors.
My next significant camera purchase was the Nikon Z6 in mid 2019. The Nikon Z6 is another camera I bought because I was curious about what it brought to the table. It has turned out to be a fantastic camera which fits me to a T, and has become my main camera. So, again, a camera bought on a whim, turns out to be a significant improvement on my system.
I will not say that the newer gear has made me a better photographer, but it has not hurt, and in many situations has made me a more effective photographer. And, indisputably, the Z6 and the M-P 240 produce substantially improved image quality as compared to the Canon 50D, Olympus E-P1 and Lumix G2 I was using in 2008-2012.
And, this has turned out to be a much longer post than I expected.
Cheers,
Antonio
P.S. I buy film cameras because they are pretty and feel awesome in the hand. Sometimes, film gets put through them.