You know I'm big on writing discipline and scoff at writer's block, usually wishing I had the luxury to complain about it (rather than do the impossible feat of trying to cram a few hundred words while the kids are messing up the living room).
However, even though writer's block per se can be overcome, if its source is actually burnout, there's only so long you can keep yourself going on a mix of determination, coffee, and chocolate.
So how do you tell between writer's block and burnout? With block, you're often avoiding a difficult plot twist or the saggy (but necessary) middle section of a book. Or maybe you are trying to force yourself to write something that doesn't really inspire you anymore. You still find creative joy and energy in writing other things, maybe nonfiction, poetry or short fiction completely unrelated to your big WIP.
With burnout, you feel like your brain has turned into banana mush, and you start wishing you would never need to write a single damn thing again, including emails, holiday greetings, and shopping lists.
Whether it's block or burnout, it's useful to step back and recharge your creative batteries. This isn't laziness or procrastination - as writers, we don't create in a vacuum. We need the right ambiance to fuel our imagination.
Books - in your genre or not, classic or contemporary, choose really good books you love (and not those in your TBR pile you have promised to beta read or review six months ago).
Movies - sometimes reading takes more energy than you currently have. Movies in your genre can really help you visualize similar settings in your own book (plus, if you write historical fiction or epic fantasy, it's a great excuse to watch Game of Thrones).
Music - I used to write to epic playlists of Lord of the Rings or ambient Saami music. At some point I stopped, figuring it's more productive to write offline without the distraction of YouTube. It turned out to be a mistake, because music really helps me to get into that deep concentration zone that's like oxygen for really inspired writing.
Scenery - a nature walk is always great on so many levels, but if it's out of reach, it may be helpful to look at albums or slideshows of beautiful nature scenery, gorgeous mansions, epic castles, and anything that might help you get into your book's atmosphere. With my Frozen World series, nowadays it's usually documentaries about Antarctica for me.
Recharging activities and digital detox - get away from social media, set your phone aside, and you'll see that the world doesn't tumble down. Roll up your sleeves and work in the garden, exercise, knit, bake, or play with your children.
Longhand - for many years, I would be intoxicated by that delightful feeling of holding a brand new notebook, feeling its weight, and envisioning the words that would fill it. Sadly, it is no longer sustainable for me to write whole novels in longhand and then type them down, but it's still a great way to get back to that mindful and passionate space in writing.
Above all, don't let writing become a chore you just want to leave behind as soon as you can. My wake-up call (literally) was the realization that I slump and nod off after writing a paragraph or two of my WIP. If my book has this soporific effect on me, what would it do to my readers? So I'm extra careful to keep writing what it has always been for me - a creative outlet and something I can't imagine my life without.