I have been with my current company for 4 years and have had to move offices 11 times. It is getting to the point where I don't unpack anything anymore. The reasons for the moves vary from simply the whim of my superiors to "we would like you closer to this or that" or "You shouldn't be in an office all by yourself so we will move you over here." They are gearing up to ask me to move again and I want to politely decline. How do I tell them I'm tired of switching so often?
Be honest, but polite. It's better to ask not to move rather than refusing to move outright, since this is still management you're talking to. I would ask to make this your last move rather than asking to stay in your current location (unless you really like where you are now). It's easier to prevent future decisions than to stop already planned actions, and it shows that you're willing to work with them on the issue.
Boss, would it be possible to find me a permanent desk? I've switched offices 11 times in the past 4 years, and having to move every 4 months is really disruptive for me. I'm willing to move again this time, but I would really like us to find me a location that works in the long-term.
Be prepared that the answer might be no. It's not clear what your manager's reasons are for moving you so often, and they may not be willing to negotiate that.
Honestly, you have no leg to stand on. They can move you every day if they want to (some offices actually don't have assigned desks). It is after all their office space containing their desks. Complaining about it just marks you as a whiner. Office space is highly political and managers have ended up spending a ridiculous amount of time on rearranging for various reasons. Just because you don't want to move is no reason not to move you because no one wants to move unless they are the people getting the better space. It may be that John needs to be moved away from Mary due to an HR issue or that team A has 4 new members and everyone has to move to accommodate them or a new manager is being hired and so someone must move out of an office because he is senior.