Because it's impossible to say exactly how much work is required before a move takes place, an estimate is central to the whole process. Doing grunt work to gets an accurate, comprehensive office moving estimate can eliminate surprises later.
Simply do not settle for estimates done over the phone or the Internet. There are too many variables that trained estimators take into account during a walkthrough that you might overlook. If a mover you contact says they can provide an estimate over the phone, move on to the next company.
When conducting the walkthrough of your current location, be prepared to show the estimator the freight elevators and loading docks, if applicable. Take them through your records rooms, spare inventory and supplies, and server closets. Better to give the office moving company too much information than not enough: the object is to avoid surprises on moving day.
If at all possible, take the estimator to the new space, as well. Simply describing your new location as "elevator accessible" is insufficient: they'll want to see the elevators for themselves.
Estimates can come in several varieties. The most common and straightforward is the non-binding estimate. The only guarantee you have is the rate — per mover and per truck, per Hr, or by weight - so your final bill can vary enormously from the original estimate.
A binding estimate specifies exactly how much the move will cost, regardless of how much the actual weight or time differs from the estimate.
With any type of office moving estimate, changing circumstances can dramatically affect your costs. If you have a binding agreement but add a basement full of old records to the move, you'll be invalidating the estimate. The same applies for circumstances beyond your control: elevators out of service or unavailable, for example.