Tax Season Checklist for CPAs: Lists to Fix First

A tax season checklist for CPAs is the list of firm documents to update before returns start arriving: client document checklists, organizers, engagement letters, Form 8867 interview sheets, reviewer checklists and request email templates. Each needs this year's forms, thresholds and dates in place by January, before the first client uses last year's version.

Which client lists should CPAs refresh before tax season?

The client lists CPAs should refresh before tax season are the per-client document checklists that tell staff and clients what to expect. Refreshing them means three passes: retire items clients no longer need, add forms that are new or newly required, and replace any dollar threshold or box number that changed since last year.

Retire items. Last year's checklist carries lines that no longer apply: a 1098 for a mortgage that was paid off, a W-2 from a job the client left, a 1099-R from a one-time distribution. Each stale line generates a reminder the client cannot answer. Mark them "not expected" with a note, rather than deleting them, so the reason stays visible.

Add forms. Clients pick up new documents during the year, and some forms change shape. For tax year 2026, the IRS Instructions for Forms 1099-MISC and 1099-NEC (12/2026) show nonemployee compensation in box 1a of Form 1099-NEC, with new boxes 1b (cash tips), 1c (Treasury tipped occupation codes) and 1d (overtime compensation). A checklist line that says "1099-NEC box 1" now points at a box that does not exist.

Update thresholds. The same instructions put the 1099-NEC reporting threshold at $2,000 for tax years beginning after 2025. Older firm templates often still print a lower figure. The IRS Instructions for Form 1099-K (12/2026) describe a third-party settlement organization threshold of more than $20,000 and more than 200 transactions. A client checklist that tells a gig worker to expect a 1099-K at a lower figure sets the wrong expectation.

Last season's additions stay on the list too. The IRS Instructions for Form 1040 (2025) introduced Schedule 1-A for new deductions, including tips and car loan interest. Clients who claimed those for 2025 will need the supporting documents again for 2026.

The best source for each client's checklist is that client's prior return. Building a list line by line from last year's return has its own guide: how to build a tax checklist from last year's return.

Updating organizers and engagement letters for tax season

Updating organizers and engagement letters for tax season means changing the questions clients answer and the terms they agree to before either goes out. Organizers need this year's forms and questions. Engagement letters need this year's dates, scope and fees. Both should be ready to send in December or early January, before documents start arriving.

Organizers

An organizer is the questionnaire and document list a firm sends each client before the season. Changes to make each year:

• Form names and boxes. Replace any reference to a box that moved, such as 1099-NEC box 1a.
• Life-event questions. Ask about marriages, divorces, births, moves, new jobs, new businesses and property sales. These answers add checklist lines that last year's return cannot predict.
• New deduction questions. Questions for items that recently became deductible, such as those on Schedule 1-A, belong in the organizer so the client knows to send support.
• Prior-year answers. Pre-fill what the firm already knows and ask the client to confirm or correct it. A blank organizer gets blank answers.

Engagement letters

An engagement letter sets out what the firm will do, what the client must provide, and by when. Each year:

• Dates. Update the deadline by which the client must deliver documents for the firm to meet the filing date, and the date after which the firm may file an extension.
• Scope. Confirm which returns are included: federal, each state, any business returns.
• Fees. Update the fee schedule, including any charge for late or incomplete documents.
• Client responsibilities. State that the client is responsible for sending complete and accurate documents.

Send engagement letters before organizers, or with them, so the terms are agreed before work begins. A firm's own counsel or professional liability carrier is the right source for letter wording; this post covers only the timing.

Due-diligence and review forms for the tax season

Due-diligence and review forms for the tax season are the firm's internal sheets for Form 8867 interviews and for the reviewer's sign-off. Refreshing them means checking the current IRS revision of Form 8867 and its instructions, updating the interview questions to match, and adding new tie-outs to the reviewer checklist for any form or line that changed.

Form 8867 interview sheets

A firm's Form 8867 interview sheet turns each question on the IRS form into a prompt for the preparer and a space for the client's answer. The IRS Instructions for Form 8867, revised November 2025, note a rule that began in tax year 2025: a taxpayer claiming the CTC or ACTC must have a valid SSN, and on a joint return only one spouse needs one. An interview sheet written before that change misses a question. Check the IRS page for a newer revision before the season opens, and update the sheet to match each question on the form.

The instructions also give the per-failure penalty as an inflation-adjusted figure, with $650 used as the example for a return filed in 2026. Training notes should take the current figure from IRS.gov rather than repeat an old one. What the form requires is covered in the Form 8867 due diligence checklist.

Reviewer checklists

A reviewer checklist lists the tie-outs a reviewer confirms before signing. Add a row for each changed item: 1099-NEC box 1a instead of box 1, the new 1099-NEC tip and overtime boxes, and any new schedule. Remove rows for items that no longer apply. The tax return review checklist shows a full sign-off sheet.

Which tax season request templates need new wording?

The tax season request templates that need new wording are the three emails every firm sends: the first request, the follow-up for clients who have sent some documents but not all, and the final notice before the firm's cutoff. Each needs this year's dates, this year's form names, and a clear list of what the client still owes.

The first request. It goes out with or after the organizer. It should name where to send documents, the date the firm needs them, and the forms the client is likely to receive and when. Update any reference to old box numbers or thresholds, and change the year in the subject line.

The follow-up. It goes to clients whose files are partly complete. The most useful follow-up lists the specific documents still missing by name and issuer: "Ridgeline Brokerage 1099-B" rather than "your brokerage forms." Generic follow-ups get generic replies. Schema CPA builds a draft of this email from each client's missing items, and someone at the firm reads and sends it; the tool never emails a client on its own.

The final notice. It goes to clients who have not completed their file close to the firm's cutoff. It should state the date, what happens after it (usually an extension), and the list of what is missing. Check the wording against the engagement letter so the two match.

A note on timing: forms arrive on a schedule. The IRS Instructions for Forms 1099-MISC and 1099-NEC say payers must furnish payee statements and file Form 1099-NEC by January 31, moving to the next business day when that date falls on a weekend or holiday. A follow-up sent in mid-February can reasonably ask for 1099-NECs; one sent in mid-January cannot.

Tax season list updates CPAs leave too late

The tax season list updates CPAs most often leave too late are the small ones: last year's thresholds in a template, old box numbers on checklists, an engagement letter with last year's dates, and a Form 8867 sheet that predates a rule change. Each is quick to fix in October and costly to fix in March.

Common examples:

• Last year's thresholds. A checklist that still prints an older 1099-NEC threshold, after the 1099-NEC instructions set it at $2,000 for tax years beginning after 2025.
• Old box numbers. Staff instructions that refer to 1099-NEC box 1 when the form now has boxes 1a through 1d.
• Copied dates. A first request with last year's due date, or an engagement letter with last year's year in it.
• Stale interview sheets. A Form 8867 sheet that does not ask about the CTC SSN rule.
• Templates in several places. The same request email saved in three folders, with only one updated. Keep one master copy of each template.
• No owner. Nobody is assigned the update, so nobody does it. Each list on the checklist below has a named owner.

Running the season itself, from assigning preparers to managing review queues, is covered in the tax season workflow category.

An example October-to-January preseason checklist

The dates below are examples for a fictional firm, Example Tax Partners, preparing for the 2026 tax year season. Adjust them to your own calendar.

The same idea for audit clients

Audit and review engagements run on a different list, the prepared-by-client request list. Firms with both kinds of client should refresh it on its own schedule. The post on the PBC request list describes what it contains, and the guide to PBC list software covers tools that track it. For a sense of what manual data entry costs a firm today, the hours calculator on the homepage estimates it from client count, documents per client, minutes per document and staff cost.

This checklist describes what IRS instructions say about forms and thresholds. It is not tax advice.