SMS or email for customer reminders? The wrong choice means reminders nobody reads and WoF work that goes down the road. Here’s what the data says, what each channel costs, and a sequence that works for NZ workshops.
97%
SMS Open Rate
Widely cited figure (Gartner); most are read within minutes
20%
Email Open Rate
Commonly cited average for service businesses
Open rate isn’t everything, though.
The Full Comparison
| Factor | SMS | |
|---|---|---|
| Open rate | 97% | 15-25% |
| Read time | Under 3 minutes | Hours to days |
| Cost per message | Roughly 10-15 cents (varies by provider) | Essentially free |
| Message length | 160 characters ideal | Unlimited |
| Images/branding | No (MMS expensive) | Yes, full branding |
| Links | Yes (shortened) | Yes (buttons, multiple) |
| Spam filtering | Very low risk | Moderate risk |
| Call to action | One link or phone number, tapped on the spot | Buttons and links, acted on later (if at all) |
When to Use SMS
SMS wins for time-sensitive, action-required messages:
Perfect for SMS
- WoF expiry reminders (2 weeks, 3 days)
- Booking confirmations
- "Your car is ready" notifications
- Additional work approval requests
- Payment reminders
SMS Template Example
"Hi Sarah, your Mazda 3’s WoF expires 15 March, 2 weeks away. Book online: [your booking link] or ring us on 04 123 4567. ABC Motors"
131 characters: fits in one SMS. Ask for a reply only if replies come back into your system. Hoist’s do: the reply lands in a thread on the customer’s file, not on someone’s personal phone, so “Reply YES to confirm” works alongside the booking link and the phone number.
When to Use Email
Email works better for informational, detailed communications:
Perfect for Email
- Detailed quotes with line items
- Invoices with full breakdown
- Early service reminders (4+ weeks)
- Newsletters and promotions
- Vehicle inspection reports with photos
Email Advantage
Email lets you include your logo, brand colours, multiple photos, detailed breakdowns, and multiple calls-to-action. It’s your letterhead.
The Best Approach: Use Both
Don’t choose one or the other. Use both strategically:
Example: WoF Reminder Sequence
4 weeks before: email
Detailed reminder with your branding, service options, link to book online
2 weeks before: SMS
Urgent, personal reminder with specific expiry date and easy booking link
3 days before: SMS
"Last chance" reminder with the booking link again
In Hoist this maps directly. Reminders are date based (WoF, CoF or next service) and each rule has its own auto-send switch, so you set an email rule at 4 weeks and text rules at 2 weeks and 3 days once, and they run from the expiry dates on each vehicle. You can also send any reminder manually whenever you like.
Consent and opt-outs
The Unsolicited Electronic Messages Act 2007 covers commercial texts and emails in NZ. A WoF or service reminder to your own customer about their own vehicle is the easy case; promotions and newsletters need consent and a working way to opt out. Put your business name on every message, give people a phone number or email to opt out with, and record opt-outs on the customer file so nobody texts them again.
Cost Reality Check
SMS costs add up. Here’s realistic budgeting:
Monthly SMS Costs
- 500 customers × 2 reminders = 1,000 SMS
- 1,000 × say 12 cents = $120/month
Worth it if even 10 extra bookings result (~$2,000 revenue)
Email Costs
- Unlimited emails in most plans
- Cost: $0 (included in software)
Use freely for early reminders, newsletters, and detailed comms
ROI Perspective
If $120 a month in SMS costs brings in 10 extra bookings at $200 average, that’s $2,000 of revenue for $120: a 16x return in this example. The question isn’t whether SMS is worth the cost; it’s whether you’re sending the right message at the right time.
Common Mistakes to Avoid
Sending novels via SMS
SMS should be short and punchy. If your message needs more than 160 characters, consider email for the details and SMS for the nudge.
Being vague in either channel
"Your service might be due" gets ignored. Specific dates and actions ("WoF expires 15 March: book now") get results.
Sending too many messages
4 reminders max for any one service. More than that crosses from helpful to annoying. You’ll get unsubscribes and damage relationships.
No clear call-to-action
Every message needs an obvious next step: "Book now at [your booking link]" or "ring us on [number]". Don’t make them figure it out. If you ask for a reply, make sure it lands where the whole team can see it, not on one person’s phone.
Start with email at 4 weeks, SMS at 2 weeks and 3 days. Watch which bookings come from each message, then adjust.