Most Canadian retirees treat the April 30 tax deadline as a finish line. File the return, pay what's owed, exhale, move on.

But filing is not the finish line. It's the receipt. It's the document that tells you what last year cost you, and, just as importantly, it sets the stage for what this year will cost you, including the Old Age Security (OAS) recovery tax that begins hitting your July 2026 payment.

With 14 days left until the deadline, here is the retiree-specific checklist most software won't walk you through, along with the move that matters far more than filing perfectly.

1. Missing a T-slip is not a small mistake. It's an automated reassessment.

The Canada Revenue Agency (CRA) receives copies of every T4A, T5, T4RIF, T4RSP, and T5008 you do. Their systems match slip data against your return automatically. If even one slip is missing, expect a reassessment letter, interest on the unreported amount, and in repeat cases a 20% penalty on the under-reported income.

Retirees are the most exposed group here. A typical retired Canadian might have income slips from a defined benefit pension, a RRIF, a spousal RRIF, two non-registered investment accounts, a GIC at a different bank, CPP, OAS, and a part-time consulting gig. That is easily eight to ten slips, often from six or more institutions.

What to do instead: Log in to CRA My Account and use the Auto-fill my return feature. It pulls every slip the CRA has on file for you. If your software shows a slip you don't remember receiving, that is a feature, not a bug. Don't ignore it.

2. Pension income splitting is the single most valuable election most couples forget.

Canadian couples can elect to split up to 50% of eligible pension income to a lower-income spouse or common-law partner. If you are 65 or older, eligible pension income includes RRIF and LIF withdrawals, registered pension plan income, and annuity payments from an RRSP.

The math is almost always in your favour. If one spouse has $70,000 of pension income and the other has $18,000, shifting $26,000 through a T1032 election can drop the higher earner out of a higher bracket and pull both into lower combined tax. Depending on the province and the gap between spouses, a well-executed split can reduce a couple's combined tax bill by 3% to 15% of what they would otherwise pay.

It can also preserve age credit room, reduce OAS clawback exposure for the higher-income spouse, and in some cases unlock the Pension Income Amount on the receiving spouse's return where they previously didn't qualify.

What to do instead: Both spouses must sign Form T1032 and file identical elections. Most tax software will suggest an optimal split if you let it. If yours doesn't, change software.

3. The Pension Income Amount is $2,000 of free tax credit that thousands of retirees leave on the table.

Line 31400 is a non-refundable federal credit of up to $2,000 on eligible pension income. It applies to RRIF income, LIF income, registered pension plan payments, and (at 65+) annuitized RRSP withdrawals. Provinces offer their own matching credit on top.

Here's the quiet trick: if you are 65 or older and you don't have any eligible pension income, converting even a small portion of an RRSP to a RRIF unlocks this credit. Withdrawing $2,000 per year from that RRIF gives you $2,000 of pension income that flows straight into the Pension Income Amount. Combined federal and provincial relief is typically a few hundred dollars per spouse, every single year, for the rest of your life.

Miss it for a decade and you've handed the CRA thousands that were yours.

What to do instead: Check line 31400 on your draft return. If it's blank and you are 65+, ask your software or accountant why. If you are 65+ and have only RRSP assets, consider a partial RRIF conversion before next year's return.

4. Medical expenses almost always beat the 3% threshold for retirees.

You can claim eligible medical expenses above the lesser of 3% of your net income or a federal floor (around $2,759 for 2025). For a retiree with a modest net income, that floor is low, and retirees accumulate claimable expenses quickly: prescription premiums, dental work, hearing aids, travel insurance, attendant care, physiotherapy, eligible home renovations for accessibility, and premiums paid to private health plans.

Two rules most people miss:

• Medical expenses can be pooled for any 12-month period ending in the tax year, not just the calendar year. Choose the 12-month window that maximizes the claim.
• Expenses should usually be claimed on the lower-income spouse's return to clear the 3% threshold faster. Run both ways and pick the better result.

What to do instead: Pull every receipt, pharmacy printout, and insurance statement from the last 24 months. Let your software optimize the window and the claiming spouse.

5. RRIF minimums, spousal RRSP attribution, and the three-year rule.

Three related items the CRA does not let you get wrong.

RRIF minimums: Once you convert an RRSP to a Registered Retirement Income Fund (RRIF), you must withdraw a government-set minimum each year. At 71, that is 5.28% of the January 1 balance. At 75 it's 5.82%. At 80 it's 6.82%. Miss the minimum and you face a 1% per month penalty on the shortfall. If your institution under-withheld tax on your withdrawals, you owe the balance at filing, often as a surprise.

Spousal RRSP attribution: If you contributed to a spousal RRSP in any of the last three calendar years, withdrawals by the annuitant spouse may be attributed back to you as income. This trips up couples who contribute in December and withdraw the following spring.

Capital gains and loss harvesting: The settlement window for 2025 losses closed in December. But you can still decide which spouse reports joint-account gains (generally the one whose original capital bought the asset) and whether to carry losses back three years to recover tax paid in 2022, 2023, or 2024.

What to do instead: Verify RRIF withdrawals against the minimum. Check spousal RRSP contribution history against current withdrawal plans. For losses, ask whether a carry-back recovers more tax than carrying forward.

6. Donations are more valuable when they're lumped, not split.

The donation tax credit is tiered. The first $200 per year gets a lower-rate credit; everything above $200 jumps to a much higher rate. A couple donating $300 each gets two low-tier claims. The same couple combining $600 on one spouse's return clears the $200 threshold once and gets a much larger credit on the other $400.

Lumping two years of donations into one taxpayer, and using pension income splitting to balance the rest, is one of the most overlooked moves in retirement tax planning.

What to do instead: Pool all household donation receipts. Claim them on whichever spouse gets the higher marginal benefit. Consider whether unclaimed donations from the prior four years should be stacked onto this return.

7. Your 2025 return determines your July 2026 OAS clawback.

This is the one most retirees miss, because it feels like a next-year problem.

OAS recovery tax (the clawback) is calculated on your net income from the prior year. Every dollar of 2025 net income above the threshold (approximately $93,454 for the 2026 recovery period) triggers 15% clawback on OAS benefits paid from July 2026 through June 2027. The return you file in the next 14 days locks that number in.

That means the moves that matter most for next year's OAS, pension income splitting, the timing of capital gains realization, RRIF withdrawal levels, charitable donation stacking, all had to happen before you sat down to file. Filing is the receipt. The work was supposed to be done in November.

If you are reading this and you're already above the threshold, there is still value in getting the pension income split exactly right and claiming every credit you're entitled to. But the bigger win is making sure you never end up in this position again.

The Bottom Line

A great tax return is a by-product of a great year of planning. If you're scrambling in the last two weeks of April to claim credits you forgot about, split pension income you could have balanced evenly all year, or harvest losses you should have booked in December, the tax return itself is already doing damage control.

This is the gap Optiml was built to close.

Optiml doesn't file your taxes. It does something more valuable: it models every year of your retirement, end to end, and shows you the moves that minimize your lifetime tax bill before December, when they still matter. Your RRIF withdrawal level. Your optimal pension split target. The year to realize a capital gain. The year to stay under the OAS threshold. The year to accelerate donations.

Every Optiml plan determines the optimal decumulation sequence across every account you own, every year of your retirement, to minimize the tax you pay over your lifetime. Canadians who apply Optiml strategies typically see lifetime tax reductions in the range of 3% to 15%, based on their specific situation.

File your 2025 return this month. Then plan 2026 properly, so next April is a formality.

Retirement planning isn't about filing a perfect return. It's about never needing to.