the offers you receive from Tier 1 (and usually Tier 2) management consulting firms are usually standardized and depend on the country of the office you applied to. Note that when I say offer I mean both the base salary, the entry bonus and the benefits (car, insurance, etc.).
The space you have to negotiate is usually quite narrow and I wouldn't expect major changes in the offer they put forward. You should definetly negotiate if the company's offer is lower than the ones their competitors make to people at your same level and with the same background (i.e. Associate joining after an MBA, Manager with 6 years of experience in operations, etc.).
Another potential reason might be that you are considering two offers: Company A offered you X to work in Amsterdam and Company B offered you X to work in Dubai, you prefer to live in Amsterdam but you would consider option B for an 1,5X salary, in this case you could negotiate but always make sure your requests are aligned to the standard in that country.
Most of the others reasons you might have to negotiate a salary (MBA loans to repay, relocation needs, necessity to have a car, etc.) are usually already taken into consideration when the company makes you the offer, if some reason they are not it is definetly a good idea to bring them forward and discuss them.
Hope this helped,