Don't sell anything to buy something new. I have done it so many times and I most always regret selling what I had. There has been a few exceptions but I would really like to suggest to keep what you have for at least a year after you start to think about selling.
I tend to change the format I like to shoot. 8x10 was my main for a few years but now I am completely in love with 35mm again and shoot old Leica cameras. Next year I could be back at 8x10