Almost every freelancer who does not take deposits has the same origin story for why they started: a project where they did weeks of work, the client went quiet, and there was nothing to show for it but an unpaid invoice. A deposit is the cheapest insurance against that, and asking for one is far less awkward than the conversation you have when a no-deposit project goes wrong.
A deposit does two jobs at once. It pays you for the early stretch of work, which is often the most intensive part. And it sorts clients who are ready to commit from clients who are still shopping, because a client who hesitates at a reasonable deposit was usually going to hesitate at the final invoice too.
How much to ask for
The common structures, and when each fits:
50% upfront, 50% on delivery. The default for most project work. It splits the risk evenly and is widely understood, so you rarely have to defend it.
Full payment upfront. Reasonable for small jobs, quick turnarounds, or first-time clients you have no history with. For a 300-dollar logo tweak, billing twice is more admin than it is worth.
Milestone deposits. For larger projects, break it into stages and take a deposit at the start of each. The client is never far ahead of what they have paid for, and you are never far ahead of what you have been paid.
The amount matters less than the principle: you should be paid for work before you have done all of it, not after.
How to phrase the request without friction
The awkwardness is almost always in your head, not the client's. Businesses pay deposits constantly, and stating yours as standard practice is usually all it takes. Put it in the proposal and the contract, not in a separate "by the way" email, so it reads as your process rather than a special demand.
A clean line: "To get started, I take a 50% deposit, with the balance due on delivery. Once that is in I will block out the time and we can kick off." Notice it ties the deposit to a benefit the client wants, which is you starting, not to suspicion. You are not asking permission to be paid. You are describing how the work begins.