I've had mine since june 2018. before that I changed it all the time. I'd decorate it for holidays, and I put the most thought into halloween usually. then sometime after the holiday was over I'd change it back to the base deer (but not since june 2018. pride is all year babey). I've been using some variation of the deer since february 2016. so I guess it depends on whether you want to count this specific image or the broader concept
and before the deer I also changed it regularly. generally between like, sets of related stuff. for a long time it was always prequel stuff. my favorite non-deer era was probably when I would use tiny little cropped sections of furry art, like these

I had several sections cropped out of each
full image and I'd switch between sections every other week or so, until I'd been through all of them that I wanted to
anyway, quick throwback to my favorite holiday deer edit of all time, from halloween 2016:
