Burnout sucks. I was burnt out for a couple years in my early 20's. Yes, my early 20's. There were many factors, mostly that I said "yes" to too many things. I was also, as I found out later, sick from food allergies, which propelled my depression. Yuck yuck yuck.
BUT, I escaped! I prevailed! And now I love my life, even without loving all of the separate parts of my life. (For more about surviving sucky-ness, see here.)
And ya know what? The core of not-getting-burnt-out is super simple.
Here are the 2 keys I learned and use today to avoid burnout:
1) Protect your Bucket
You need to know what you can do and what your can't. Where is your line?
You have ONE bucket, and you only have so much in there to give. Burnout is the result of continuing to give when your bucket's empty.
BE INTENTIONAL with your time, energy, and heart. CHOOSE where you're going to give, and where you're not. Have some boundaries and learn to say no to the things that really don't deserve that precious stuff, and say yes to pouring into the people and projects you've chosen specifically.
2) Fill your Bucket
In addition to protecting your bucket, you need to be pouring back into your own bucket. What makes you come alive? What makes you feel awesome? What's beautiful to you? These things fill your bucket.
On a simple level, it could be taking a walk. On a deep level, fulfilling your destiny. It's up to you to figure out what makes you come alive, and include those things in your life.
One common mistake is jumping your stack.
This is typically skipping your second function and deferring to the third. Example: As an FiSe (ISFP), I have a tendency to ignore my Se and its needs altogether and just focus on my inner Fi-Ni world. Of course Te (my fourth function) butts its head in, but the second function isn't that aggressive.
To give an extraverted example, an NeFi (ENFP) will very quickly burn out if they ignore their Fi (second function) and just hang out in Ne-Te land.
The second function may be the often-forgotten-middle-child, but others can be skipped to. Take a look at your life and see if you're valuing and exercising the right things.
You are worth it. And heck, the more your pour into yourself, the more you have to give.
Fill that bucket.