I am not immune to burn-out, I've experienced it many times, but luckily I can't stand idle so whenever I finish a game I almost immediately start a new one (like I am doing now). In 15 years I haven't had a single month of full break. But I'm not a normal person 
I think the important (in my job) is to alternate tasks. When you're burned out is hard to find the inspiration to write so I just code or do other things
