This posting is part of my “Thoughts on Employment” series, detailing some lessons learned and general musings from my career as a software developer on what an employer can do to provide an effective, productive and attractive work environment for highly effective software development teams. For an introduction to the series and an index of postings in the series, please read my introduction post.
Burnout can be a pretty big problem in the tech industry. You should have a plan in place for preventing burnout and for handling it once it occurs. On the prevention side, keep an eye on long periods of "crunch time". If the norm for your project is 50hr or more work weeks, you've got a problem brewing. Limit the long hours to when they're actually needed (and if you think they're always actually needed, then you're understaffed). When they do occur, show your staff their extra time is appreciated by ordering-in dinner, or having a launch party once it's done. And put a concrete condition on when it ends: if that's "when X is done" then make sure you've clearly defined "done". Moving that condition by changing scope or adding conditions can kill moral.
Then, if an employee is showing signs of burnout, have a plan for how to handle that. Consider this a part of your retention plan. Consider changing something about their day-to-day job - maybe a different project, different work hours, maybe some time off. Just make sure you apply this fairly across employees when burnout occurs (where "fairly" can take tenure and seniority into consideration).
Just remember: employees want to hear that you have a burnout prevention plan that will keep them from hating their job. They might not like hearing you have a plan for handling burnout when it occurs, because this implies it occurs with enough frequency that it needed a plan and no one wants to hear that burnout is a frequent occurrence at their job. But the truth is that burnout is an issue in our industry and results in extended reduced productivity and in many cases the employee leaving, which is expensive for an employer, both in lost opportunity costs, as well as recruiting cost to backfill the position. Plus, if your team as a whole is suffering from burnout, having one person leave can snowball, as other team members taking that as an example and following suit - resulting in a difficult to overcome cycle of fill-the-empty-seat.