I've suffered a serious burnout once and a close call one other time. As with many things, recovering from going too far is harder than not going too far in the first place. Having said that, there are far too many people in IT who are "knowledge static" (my term). They either learnt somethings and decided that was enough or just muddle through never intentionally improving themselves.
This editorial highlights that continuous improvement is an essential, albeit slow, never ending task.
Of course, the sheer fact that we are here on SQLServerCentral.com probably means that we all have already accepted this ;-)
-- Stop your grinnin' and drop your linen...they're everywhere!!!