This is a huge career issue for Stage Managers. I have been working pretty much straight for the past ten years, the longest I have NOT been working on a show was one six-week break I took, the rest of the time, the longest time between shows was ten days. I have been at my current job for six years, 52 weeks a year, most of the time in rehearsal (doing up to six shows a year). And I was reaching a breaking point; luckily I know myself pretty well, and started to look for the "next thing" to keep my mind, my body, my soul challenged. When you get bored, things begin to irritate you – as things begin to irritate more, you are pushed to the burning out mode – at least that is true in my history. I know about three years in any sort of given circumstance, and I start needing something new in my life . . . part of this is from the fact my parents moved the family every three years as I was growing up.
You have to learn yourself, and know WHY you do this job. There are two types of burn out - the day to day, and then sort of the more long term "Career" burn out.
As far as the day to day - take care of yourself - eat right, get some sleep, laugh, drink water, learn to delegate, learn to say "no". Too many people try to be Superman or Superwoman as a stage manager, remember you are human, with all that good that comes with that.
Now, as far as career burn out - take care of yourself on the day to day level, but learn to look ahead - somewhere keep that early career mentality of future plans - where do you want to be in one year? five years? ten years? Don't loose sight of running your career like a business, and make sure that you are taking care of the business. Figure out WHY you do this job? Are you getting your needs met? Are you getting the challenges you need? Remember, no amount of money makes up for some of the downsides of this career - including the time suck this career can take. You need to make sure you are getting your intangible needs met.
My helpful advice to anyone going through the "Am I burnt out?" question - is question what is changeable in your life that can make your career more fun, more stable, more exciting, more challenging . . . are you geographically bound? Look into moving. Are you stuck in one theater? Try working at a new theater. Do you need to move a level? Work in a smaller theater? Work in a larger theater? Try dance, opera, music, circus . . .
Take a vacation . . . if you are a freelancer, you need to program down time. If you have a full time position, make sure to take the downtime. AND REALLY RELAX. (Learn how to relax . . . a lot of stage managers, myself included, don't know how to relax, disengage.)
Make other things important in your life - date, get a pet, have a hobby, spend time with your family, spend time with strangers outside of theater - whatever. But, if THEATER isn't the only thing in your life, then when you career gets "irksome" and pushes you to burn out . . . you will have other things that can help stabilize and ground you.
And remember, they may come time when you are “done” stage managing. There is no rule you need to keep doing this for the rest of your life. The skill set and experience you gain as a stage manager can easily transfer to other jobs, other careers. And remember, there is no rule if stop stage managing to do something else that you can’t come back.