Why YSK: Doing so can change your feed and experience drastically.
I typically sort by local/all: active, where I see a mixture of memes, news, and discussions. But I switched to all: hot, and I was shocked by just how homogeneous my feed became. It was pretty much entirely memes and computer discussion. Obviously this isn’t always the case. But, I could see someone who always sorts by hot not realizing the diversity of the site.
So, if you’re a little bored with your feed, or just want to see different posts, then try different sorting methods. Even if you’re not, try it anyway. You might like what you find - or you might go back to your default.
My default is actually “New”, I only manually change to Hot or Active if I want to see some comments and discussions.