While I really like gear, I don't thinks it's at all necessary. Wearing a tail (when I had one) definitely helped me feel more at home in my skin b/c I'm almost constantly p-shifting w/ my tail, but it's never been 'I need it' for me. I also tried collars for a bit and it didn't really do anything for me. If anything, it was uncomfortable both physically and mentally with the looks it'd get. I think the biggest part of gear is the stigma it has around it. Since there are so many canine therians, the idea of wearing tails, collars, and ears has been very, idk how to word it, but, like, common I guess would be the right word. Like, when I first realized that I was a therian/when I found the community, the biggest thing that was in front of me was 'gear'. Youtube therians and the topic itself was such a big one that I sort of felt like I needed gear to be a therian, which is by no means true. Wearing it did make me really happy because it helped me feel like I was 'real', but, as I mentioned with my experience wearing a collar, it wasn't practical or what was good for me.
Sum: Gear is great to help ease dysphoria, but by no means necessary. Do what makes you feel good.