What you hold at the end is the whole operating picture rather than a folder of files. Every account is already in your name with you as the owner, so nothing is transferred because nothing was ever held. You have the working site, the source files, the analytics history, and the advertising accounts with their data intact. Alongside that you have documentation of how things are set up and why, which is the part that usually goes missing: not just the passwords but the reasoning, so the next person you work with inherits decisions rather than guesses.
The last stretch of the engagement is deliberately different from the first. Rather than building new things, we work through what happens when something breaks, how to publish and update without help, which numbers to check and how often, and what should change as you grow. If a handover requires a long meeting to explain, the work was not documented properly, and that is a failure on my side rather than a gap in yours.
After that I am genuinely out of the picture, and the reason is not sentimentality about scope. A business that still depends on the person who built its foundation twelve months later has a problem, and I would be the problem. What tends to happen instead is occasional contact: a question before a decision, a second opinion on a proposal from somebody else, an introduction to a specialist who handles the stage you are entering. There are agencies and consultants who do scaling work better than I do, and pointing you at the right one is part of finishing the job.
The practical answer to what you should do in that final stretch is prepare for year two rather than closing out year one. Audit the tools you accumulated and cancel what you stopped using. Decide which of the manual processes you have been tolerating should become systems before you hire. Look at where your customers actually came from and put the effort for next year there instead of where you guessed at the start. Those conversations are part of the engagement, and they are more valuable than anything else built in the last month.