The end of the year is a great time to do an audit.
I suggest looking at the following.
Content. What content needs to be removed, updated, or created fresh?
Events. What events performed above average, average, or below average to goal?
Buying experience. What parts of the buying experience are filled with too much friction, which parts are just right, and which parts could be optimized more the buyer?
Website. What pages need an update, which pages have underperforming KPIs to benchmarks, and what pages need to be created?
Email. What emails are performing above, below, or at the benchmark, and why?
Of course there are many more things you could audit.
Sometimes the best place to start with an audit is looking at your marketing budget and seeing what you're spending the most money and time on (including people) and start at the top.
The key to a good audit is context though.
Making sure you're looking at the audit through the right lens.
The lens should be ICP focused and looking at the accounts who became actual customers over the last 12 months.
Are they seeing value and have a good health score, and are on a path to renewal?
An audit that looks at vanity metrics isn't very good. Might do more harm than good.