Don't get so involved in technical details that you don't pay attention to the business. Your company will try to stab you in the back one day, so you have to

Don't get so involved in technical details that you don't pay attention to the business. Your company will try to stab you in the back one day, so you have to keep an eye open for it. Always reserve 1% of your career energy towards looking for a new job greater than or equal to your current job. Whenever you find one, take it, and just keep on looking. (If you do contracting, never let any single client represent more than 50% of your total income.) It's harder for them to hit a moving target. And even if they do get you, they're more likely to just wing you instead of hitting something vital.