The answer decides almost everything else. Here is how I think about it:

1. Want full control and high speed?
   A centralized exchange gives you your own listings, fee rules, and a fast matching engine. Traders who want quick execution and deep order books usually prefer this model.

2. Want users to keep their own keys?
   A decentralized exchange lets people trade straight from their wallets. It is more transparent, but you need to plan liquidity carefully or the pools stay empty.

3. Building for regions with limited banking access?
   A P2P exchange with escrow works well here. Buyers and sellers deal directly, and the escrow protects both sides.

Once the model is clear, the next step is picking a partner. A good crypto exchange development company should ask about your users, your liquidity plan, and your compliance needs before it talks about code. If a vendor jumps straight to a quote, that is a warning sign.

A few things I would always confirm:

Do they support KYC and AML inside the build?
Can they show how the wallet and withdrawal security works?
What happens after launch when bugs or upgrades come up?

Which model would you pick for a new project today, and why? Share your experience below, especially if you have faced liquidity or security problems.