Any cleaning company that quotes without seeing your building is guessing. A walkthrough is where the real price gets worked out, and it's also your chance to see how a company operates before you commit.
What happens on the day
Someone from the company walks every area to be cleaned, measures it up and notes the floor types, the number of desks, kitchens and washrooms, and anything sensitive. They'll ask about access hours, existing routines and what's caused problems before.
It usually takes 20 to 45 minutes for a normal office, and there's no charge.
What a good company will ask
Good questions include: when is the building quietest, who holds keys, what standard do you expect, what has gone wrong with previous cleaners, and are there any areas that need special care? Someone who only asks about square footage isn't working out what you need.
You should also be asked about extras, such as windows, carpets and supplies, even if you don't need them yet.
How to prepare
Have your access hours, security rules and any current cleaning schedule to hand. Note the rooms that matter most, like reception and meeting rooms. If you have a budget or a comparison quote, say so.
Afterwards, you should get a written quote, ideally within 24 hours. See how to start yours.
A quote you haven't walked the building for is a guess with a price on it.
The short answer
Expect a free visit, plenty of questions and a written quote afterwards. Be wary of anyone who prices your office from a spreadsheet.