When to Look for Another Job

I have had the lucky(?) fortune for working for one employer. I was hired as an intern my Senior year in college and then became a full time salaried employee a month before I graduated. Overall this company has been great to work. Besides the usual complaints about the boss, I have it pretty good. Being on the "creative" side of our business, I don't have to dress up for work, nor do I have to deal with customers. We have great benefits, including a 50% matched 401(k) vested at the end of the year and Restricted Stock Awards with the same vesting. As I have grown with this company I have been promoted and have begun to get even more Restricted Stock (that usually I have full access to within a year) and even earned an entire week of extra vacation time. Also, year-end bonuses roll in at about a 5% average (higher if promoted). As some of you may know, I am currently seeking my CFP and the tuition is fully reimbursed by my company. I have even been allowed to hand off some of the work I feel is tedious and have begun to work in the FP side of our business. While I love what I do creatively, my company is allowing me to now do both of the things I have great interest in. I know everything seems peachy regarding my job and the 6 years I have worked at this company, but my finances are recovering from the mess I made a couple of years ago (more to come on this in the future).

I have no reason to leave this company, but if things still go this way, why would I ever leave? I truly enjoy my job and the creativity I get to exude, but when do you decide to leave and work for another company?