Don't let bad data cost you this Black Friday

Black Friday is the biggest trading period of the year for most Australian retailers. Australians spent $8 billion online over the Black Friday period in 2025, up 9.3% on the year before. It's also the worst time to discover your data is in poor shape. Problems that are easy to absorb in a quiet week - a returned parcel, a bounced email, a failed SMS - stack up fast at full volume. There are two things to get right: what you're collecting at checkout, and what you're cleansing from your existing database.

Address data is more complicated than it was

3.1 million households shopped online over BFCM weekend in 2025. At that volume, a bad address isn't a minor inconvenience. It's a return, a support ticket and a customer who won't come back.

Collecting accurate address data at checkout is the first line of defence. Australia Post changed how Parcel Locker and Parcel Collect addresses work this year, and that affects how address data needs to be captured and stored. If your checkout isn't handling the new format, valid addresses get rejected and orders fail to process.

Cleansing your existing database matters just as much. Old-format Parcel Locker addresses in your customer records won't process correctly under the new rules. At Black Friday volume, that means failed deliveries at exactly the moment you need everything to run smoothly. The frustration lands on the retailer, not Australia Post.

Read our full breakdown of the Australia Post Parcel Locker changes.

Your email list decays whether you send or not

Industry benchmarks put annual email list decay at around 22.5%. People change jobs, abandon old accounts and move on. If you're collecting email at checkout without verification, bad addresses enter your database from day one. If you haven't cleansed your list recently, a large portion of your Black Friday send won't reach anyone.

Some of your customers won't see the deals you've lined up for them. The bounce rate climbs, and your sender reputation takes damage that affects deliverability on every campaign that follows, not just this one.

Phone data fails quietly

Bad phone numbers don't announce themselves until something goes wrong. An SMS campaign reaches only a fraction of your database. A customer who bought online doesn't receive their delivery notification and contacts support instead. Australia Post's parcel redelivery process is relying on accurate mobile numbers more heavily now - if that data isn't right, the notification fails and the parcel sits uncollected.

If you're not collecting valid phone numbers at checkout, the problem grows with every order. If you haven't cleansed your existing records, you won't know the scale of it until peak season exposes it.

Before you go live

Collect

• Make address, email and phone required fields at checkout
• Add verification to those fields so bad data can't enter your database
• Check your checkout and logistics handle the new Australia Post Parcel Locker address format

Cleanse

• Clean your email list before your Black Friday campaign goes out
• Verify delivery addresses in your customer database against the current Australia Post dataset
• Check that phone numbers in your existing records meet basic format requirements