I'm currently in a very stable, comfortable dev position where most of my growth as a developer is solo. My current team doesn't really discuss software development and not everyone is interested in it enough to grow as a group. Nevertheless, I love the people I work with and we have the opportunity to work on fun projects (most of the time).
Through a recruiter, I've been offered a very exciting job with a bunch of super-smart devs that love to discuss, improve, grow. However, (and the employer doesn't know this), I'm planning on leaving the area in just over a year. These plans are pretty definite, so the mentality of "Hey, anything could happen in a year," while true, doesn't feel applicable.
There are other factors to consider (a much longer commute, longer working hours, etc), but the one that is really bothering me is I don't know how I feel about starting something so life-changing, only to start making plans to leave in ~9 months. Personally, I want to feel like I'm settling into a job, not hopping around. Granted, I also can't help but consider the needs of the employer; I don't want to be the guy that stayed for just a year, forcing them to restart the hiring process.
Especially in the field of software development, I feel there's an investment made in the employee that is hired. (Training in the business domain, training in the specific practices of the organization, training in the tools, etc.) I'm the kind of developer that wants to give back on that investment -- otherwise I feel I have nothing to show for myself.
So, do you think a year is enough time to give back on that investment?
Edit: I appreciate all of the answers I've received, but I wanted to clarify that I wouldn't be leaving in 9 months, I'd be leaving in 12-13 months. 9 months was just an approximation of how long until I had to start thinking about leaving.