What to gather in the first two weeks
A new client engagement lives or dies on what happens before the first month-end close, not during it. If you spend the first two weeks scrambling for documents you should have asked for on day one, you'll be behind for the rest of the engagement, and clients notice a shaky start more than they notice a smooth middle.
Ask for everything up front, even the pieces you won't touch immediately: statements for every bank and credit card account, going back at least to the start of the current fiscal year, and further if you'll be doing any catch-up or cleanup work. Prior financial statements or tax returns, if they exist, give you a baseline to check your own numbers against. Access to their existing accounting software, if any, tells you what you're inheriting. And a full list of accounts, including any that are closed but still relevant to open transactions, prevents the awkward discovery three weeks in that there's a fifth account nobody mentioned.
Get this in writing during the sales conversation or the engagement letter, not as a series of follow-up emails. A short, specific document request list handed over at signing does more to prevent delays than any amount of politely worded chasing later.
Reconstructing opening balances
Almost every new client arrives with books that don't quite tie out, even the organized ones. The fix is to stop trusting the existing ledger as your starting point and instead anchor to the bank statement.
Find the statement that covers your intended start date, and use its ending balance as your opening cash balance for that account. Everything from that point forward gets built from actual bank activity, not from whatever was previously entered into QuickBooks or a spreadsheet. If the prior ledger's balance on that date doesn't match the statement, that gap is data you need to investigate, not a rounding error to ignore. Sometimes it's an uncleared check, sometimes it's a mistake that's been compounding for years.
This is also where working from PDF statements pays off even for clients who do have a bank feed connected. A feed typically only reaches back a limited window, and you often need the statement from a year or more ago to properly anchor the opening balance. See reconstructing a year of transactions from bank statements for the full version of this process when you're rebuilding more than just an opening number.
Turning a pile of statements into usable data fast
New clients rarely arrive with one clean statement. More often it's a dozen PDFs across several accounts and several months, sometimes years, sitting in a folder or an email thread. Entering that by hand isn't just slow, it's exactly the kind of repetitive work where errors creep in unnoticed.
A PDF-to-spreadsheet converter changes the math on this entirely. Instead of retyping transaction by transaction, you convert each statement, get back a spreadsheet with the running balance already checked against what the bank printed, and move straight to import. bankstatement.dev handles this conversion and exports to CSV, Excel, or a ready-to-import QuickBooks file, which means a backlog that would have taken days of manual entry becomes a task you finish in an afternoon.
This matters most in exactly the first two weeks of a new engagement, when you're trying to establish trust with a client by showing up organized and fast, not buried in data entry for a month before you can show them anything.
Setting up the chart of accounts and categorization rules
Once the historical data is in, resist the urge to accept the client's old chart of accounts wholesale if it's cluttered or inconsistent. Onboarding is the cheapest time to clean this up, because you haven't yet built months of categorized transactions on top of a messy structure. Consolidate accounts that don't need to be separate, and set up categorization rules for recurring vendors and transaction types early so they apply automatically going forward instead of requiring manual review every close.
This is also a good moment to flag, and document, any transactions that clearly cross the line between business and personal spending. Getting ahead of that conversation at onboarding is far easier than raising it six months in — see separating business and personal expenses for how to have that conversation without it feeling like an accusation.
The onboarding checklist you can reuse every time
Bring these together into a repeatable sequence rather than reinventing the process for each new client: collect account statements and prior financials at signing, confirm the full list of accounts including closed ones, convert any PDF backlog to spreadsheets and reconcile against printed balances, anchor the opening balance to the bank statement rather than the old ledger, and clean up the chart of accounts before you start entering ongoing activity.
Written down once and reused for every new client, this checklist turns onboarding from a source of anxiety into a predictable two-week process, which is exactly the impression you want a new client to walk away with.