Stress

That depends. Do you have reasonably computer-literate users? Do you have enough funding to keep the network on a proper upgrade schedule? Do you have adequate support from management when you need to pause production to implement security updates? If you can answer "yes" to all of those, you should be in pretty good shape as far as stress is concerned.

If you can't answer "yes" to any of them, you might have to worry about premature greying of your hair. Best of luck.