it could be a good idea to start to prepare for non-MBB companies first; however, I would not distance applications more than a couple of weeks. That’s because:
- Applying first for non-MBB could help you to feel more confident with MBB (even if you have practiced a lot before, in the very first interview you will do, you will probably not perform as well as in the following ones)
- Not putting too much distance between non-MBB and MBB interviews will help you to avoid having to choose an offer without chances to interview with MBB.
Normally, you will have 1 or 2 weeks to sign a contract; ideally, you may want to use that time to leverage the offer from the non-MBB in order to speed up the process with MBB. This is what happened in my case: I got first a OW offer, and then managed to get all the BCG interviews in 4 days and all the Bain interviews in 1 day. That’s because an offer from a leading competitor will validate you and push the other companies to proceed faster (and potentially decrease the number of interviews you will have to do) in order not to lose you.
Even if you start from non-MBB, there are no guarantees you will not be called by MBB first, as each company has its waiting periods before interviews based on the amount of projects they are dealing with. However, applying for non-MBB first you will maximize the chances to follow the previous mentioned plan.
Hope this helps,