Also: be careful of agents. Don't give out too much information to them, just bare bones. I would not let them in on the 3 year time frame, just tell them the standard 1 year for now. Understand that the agenda of most agents (make the highest quick commission they can) is in conflict with your interests, and most of them are fairly unprofessional as anybody off the street can become an "agent". Do not be pushed into any apartment or any situation you feel uncomfortable with. Take your time. For 3 years, get the right apartment the first time if you can. I suggest that you enter into a 12 month lease only, with renewal privileges. Sometimes things happen and you want to leave yourself an exit position and the ability to move on. The apartment may not turn out to your liking, your situation may change, etc. etc. Or some external factor like building construction on the next door property could intervene. Leave yourself wiggle space. At any rate, rents in Beijing are not rising so fast (if at all) that you run much risk of being stuck at renewal time with a huge rent increase. Highly unlikely.

You many need to have more than one agent looking, as the system here is fragmented and inefficient. Some apartments are in some sort of central database accessible by multiple agents, but many are listed by landlords with exclusive or very few agents. Your first agent won't like the competition, but that's tough and that's the real estate business here. Just keep a notebook record of what units you look at, and to prevent future arguments, only look at a specific unit with one agent--if another one wants to show you the same unit, say "No, I've already seen it with a different agent, what's next on your list?" If you really like a complex but not the unit one agent showed you, call up another agent and specifically ask if they have "any 2 BR's in Complex X"--chances are good they might, and it will be different unit(s).

Also look beyond the unit itself--at the grounds, noticeboards, condition of common hallways, etc. It can tell you a lot about the way the place is managed. In Beijing, quality Management is often all that stands between your peace, comfort, and sanity, and residential chaos. In general, the stricter they enforce rules and regulations, the better for your quality of life. (Well, at least this is the position a lot of foreigners take.) It is instructive to visit your finalist properties in the early evening when people are coming home and you can see who's living around you. This can be done alone and without agent if you don't need to see interior of unit again. I've done these reconnaissance missions and crossed a few things off my list after doing this. Sometimes it's a gut-feel thing.

If you find the perfect unit but the furniture is a little tatty or poor taste, ask the agent to inform the landlord and see if anything is negotiable. Lots of landlords will replace furniture and appliances with new stuff, especially if it's a bit old or in poor repair. And if new, often they'll let you pick out, or pick out style, or whatever. Never hurts to ask.

I have just concluded an apartment search (moving within the city), and had to get 3 agents...which was a bigger hassle but allowed for more coverage, faster. For comparison, in about 5 days I looked at 16 apartments within about 6 different complexes. Which for me is unusually small (previously in Beijing, I've been known to look at 40-50 different units in 10-12 places before selecting...but I'm extraordinarily picky). And remember, you may not get everything on your wish list but have to compromise on one or more aspects. Just make sure you don't compromise on the top priority criteria.