Jeff Atwood (of CodingHorror) recently left StackExchange after four years of really hard work. He gave his reasons in a farewell to StackExchange - explaining that he has realised that, as amazing as it is to work on a brilliant project... it's not worth missing out on your children.
To this I'll add a recent Ignite talk: Go the fuck home by Pam Selle
I totally agree.
Anything over a 40 hour week is really stupid. Not just for you, but also for the business you're working for. Many good books have pointed out that, not only do you not do your best work after five... but sometimes you can be actively sliding backwards (making more bugs that have to be cleaned up).
Of course the business won't say no. They think they're getting extra work from you for free... But remember that old deathbed adage about nobody feeling like they should have spent more time at the office.
Don't ever forget that any extra time at work is at the expense of your most precious commodity - your own life.
You only have one, and it's shorter than you think.
Get Real about how you're spending it.
You really don't win anything by giving it away for free to an employer that *maybe* might pat you on the back and give you a tiny pay-bump when your next review comes around.
yes, some companies are amazing, wonderful places to work for and you truly enjoy being there, that's great.... but this is the exception, not the rule, and even so - think about Jeff Atwood. StackExchange really is one of the really amazing places... but it still isn't Your Life (the only one you've got). So really think, then think again about your priorities here.
I know what it's like. Your boss tells you that it's critical to hit the next deadline and all but orders you to pull an allnighter? You do know they actually cant enforce that don't you?
Afraid you might lose your job? yes, you might... and then you might go find one where they treat you like a human, instead of a "business resource" to be pushed around at will.
Again, unless you're in a rare position, you probably aren't building the cure for cancer... and that deadline, while it might hit the company's bottom line today, probably won't cause people to actually die if you miss it... but what will happen is that you will continue to prop up a company that has very poor planning skills - and that is willing to exploit its workers at the expense of their time, health and sanity... and you're helping them do it?
Go the fuck home!