Even when you're comfortable in your current job, it's a good idea to make notes about your existing responsibilities and key achievements on an electronic copy of your resume. It's so easy to forget the details as you continue to grow in your career - by keeping notes as you go along, you can avoid the hassle of hunting down that info when you need it most! Having your work history ready at hand when it's time to start looking for a new job can be very useful, but having a record of your successes can also be a great negotiating tool when you're up for your next performance evaluation or asking for a raise.
Some things to keep track of include special projects you work on, process improvements you suggest, internal controls you introduce, awards you win, rankings compared to other personnel at your level, increases in profitability or sales you contribute to, business relationships you develop or repair, committees you serve on, lawsuits you help avoid, training materials you create, and so on.
I'm a certified career coach based in Philadelphia. I started my own practice to help people land their dream jobs and achieve their individual definitions of success.
I also keep this blog with my musings on changes in the employment landscape, advice for job seekers, links to other career-related articles, and anything else that catches my interest.