Advice on keeping connected no matter where you are in your career from Lifehacker.
Just Starting Out: When you’re looking for your first job, or first transition to a new job, reach out to your family and alumni. Both are groups that you already have a connection with, which helps when you haven’t been working long enough to build a strong network.
Three to Five Years In: Look to a former manager for a mentor or solid referral as you make the jump up the career ladder to other opportunities. If you’re interested in taking on a junior-management role, a recruiter can help you find the right position.
Mid-Career: Former coworkers who are now at other companies are a strong source of referrals when you want to move jobs, or even switch careers.
Senior Level: If you want to find open senior level roles, keep in touch with people you’ve managed before and been a great boss to. They’re the ones who can vouch for you and let you know when senior positions open up at their companies.