I transferred after ~3 months because my original team wasn't a good fit for me. One of the topics that is mentioned during orientation is that Google is designed to be fault tolerant at multiple levels. If a server goes down, the workload needs to be able to move to a different server. If a Noogler is placed a team that isn't a good fit for their skillset, they need to be able to move to a different team. This happened to the person giving the orientation when he was first hired and it still happens today. Some people end up quitting because they can't adapt, while others successfully recover from the error.
that's weird, because my experience is exactly the opposite! I've spent about 4 months on my team so far, which has very little to do with my background, and after I realized just how bad the fit was, I started a conversation with my tech lead, his supervisors, and some HR people about moving to a team that would be a better fit (which had openings at the time).
3 weeks of conversations later, I was told that the 18 month rule was "fair" in everyone's opinion, and that if I'm really concerned about working on projects that are interesting to me, I should just find one to spend my 20% time on (easier said than done).
