Should we collect phone numbers in the same form as email?

Separate the consent, always. Bundling them costs you email signups because the phone field raises friction at the worst moment, and it puts your SMS consent on shakier legal ground since the disclosure is muddied. Capture email first, then invite SMS opt-in later from people who have already engaged — smaller list, far better economics.

Which channel should get the abandoned-cart flow?

Both, sequenced, with SMS second. An email within the hour catches most of the recoverable value at no marginal cost. A single SMS at a longer interval — often around a day — catches a meaningful slice of the rest and is one of the few automated SMS uses that reliably pays for itself. Sending both immediately just pays twice for the same order.

Is email deliverability really still a problem?

It is the problem, and it is usually misdiagnosed as a content problem. Authentication records, list hygiene, engagement-based segmentation and sending reputation determine whether your email arrives at all; subject lines only matter afterwards. Brands that move budget to SMS because email stopped working have almost always got a deliverability fault they never fixed, and it will follow them.

Comparison

One is nearly free. The other costs per send.

That single difference drives every other decision — what you send, how often, and how quickly you can burn a list you spent a year building.

Our bias, declared

Most brands should build email first and add SMS for a narrow set of time-sensitive moments. SMS produces higher engagement rates that make it look better in a dashboard, but it carries a per-message cost, a far harsher consent regime, and a list that punishes overuse permanently. Email's economics forgive experimentation; SMS's do not, and treating SMS as a second broadcast channel is the most common way we see brands destroy an expensive asset.

Side by side

Email vs SMS marketing comparison
Factor	Email	SMS
Cost per message	Effectively zero at volume	Real per-segment cost, every send
Open / read rate	20–40% typical	Read almost immediately
Speed of response	Hours to days	Minutes
Consent requirements	Straightforward opt-in	Express written consent, tightly regulated
Legal exposure if you get it wrong	Deliverability damage	Statutory damages per message
Room for content	Unlimited, designed	A sentence and a link
Tolerance for frequency	Several a week if segmented	Two to four a month before churn
Cost of a mistake	Send an apology	You paid to annoy everyone
Suitability for urgency	Poor — competes with a full inbox	Excellent
Revenue per subscriber per year	Higher in absolute terms	Higher per message, smaller list

Choose email when

The message needs more than a sentence

Education, storytelling, product explanation, anything with more than one link. SMS forces you to compress everything to a line and a URL, which works for a reminder and fails for an argument.

You want to experiment

Zero marginal cost means you can test subject lines, segments and cadence without spending anything but attention. Every SMS test costs money per recipient, which is why SMS programmes tend to ossify around whatever worked once.

Your list is large and your margins are thin

At a hundred thousand subscribers, a per-message cost turns a broadcast into a meaningful line item. Email's economics scale with your list; SMS's economics work against it.

You need an owned asset that compounds

An email list is portable, exportable and outlives any platform. It remains the most durable owned audience available, which is why it survives every prediction of its death.

Choose sms when

The moment is genuinely time-bound

Back in stock on a product they asked about, an order out for delivery, a flash window closing tonight, an abandoned cart within the hour. SMS earns its cost when the value of arriving now is real, and only then.

Your customer is not an inbox person

Some audiences — younger, mobile-first, or in categories where nobody reads promotional email — simply do not open. If email engagement is structurally weak after you have fixed deliverability and segmentation, SMS may be where your audience actually is.

The transaction is high-frequency and low-consideration

Food, convenience, ride-hailing, anything repurchased weekly. The message is short by nature and the decision window is minutes, which is exactly SMS's shape.

You need a channel email cannot reach

When deliverability has collapsed and rebuilding sender reputation will take months, SMS reaches customers who are no longer seeing your email at all. Treat it as a bridge, not a replacement.

The economics people get wrong

SMS dashboards report engagement rates that make email look broken — read rates near total, click rates several times higher. The comparison is misleading because the lists are not comparable. An SMS list is smaller, more recently opted in, and self-selected for people who wanted messages badly enough to hand over a phone number. Compare revenue per subscriber per year rather than rate per send, and the gap narrows sharply.

Then add the cost side. Each segment of each message costs money, and a message over the character limit silently becomes two. A monthly programme to fifty thousand subscribers is a real recurring expense that email at the same list size effectively is not. Model it as cost per incremental order, not cost per send.

The consent regime is the part that carries genuine risk. SMS marketing in the US requires express written consent with specific disclosure, and statutory damages apply per message — a badly built list is not a deliverability problem, it is a litigation problem. Buying or inferring phone numbers is the fastest way to turn a growth channel into a legal one, and no engagement rate justifies it.

Related questions

Two to four messages a month for most consumer brands, and treat every one as spending down a balance. Opt-outs on SMS are permanent and immediate in a way email unsubscribes are not — people churn from a text list faster and never come back. If your calendar has weekly SMS on it, you are converting a durable asset into one quarter's revenue.

Other comparisons

Marketing agency vs in-house teamNot budget, and not company size. It depends on whether you already know which channel works — because that single fact changes the right answer completely.Marketing agency vs freelancerWe say this on sales calls regularly. Under roughly $10,000 a month in media, agency fees eat too much of the budget to be honest value.How to choose a digital marketing agencyMost agency selection processes evaluate the pitch rather than the agency. These are the questions that produce genuinely informative answers.SEO vs PPCSEO compounds and pays back slowly. PPC starts immediately and stops the moment you do. Which one you can afford to wait for is the whole question.Shopify theme vs headless commerceIt buys genuine speed and flexibility, and it buys them with permanent operational complexity most stores don't need.Retainer vs project pricingEach model creates a different incentive, and matching the model to the work matters more than negotiating the rate.Google Ads vs Meta AdsIf people already search for what you sell, start with Google. If they don't know it exists, Google has nothing to capture.Brand vs performance marketingPerformance work is measurable and brand work mostly isn't, so budget flows to what can be defended in a meeting rather than to what works.Performance Max vs Standard ShoppingThe performance difference between them is smaller than the reporting difference. What you are really choosing is how much you are willing to not be able to see.Last-click vs data-driven attributionAttribution does not measure causation and was never able to. The question is not which model is accurate — it is which set of errors you can work with.Full rebrand vs brand refreshThe symptom is usually that the brand looks dated. The diagnosis is almost never that the brand is wrong — and those two problems have very different price tags.Webflow vs a custom buildMost companies pick the platform once, at the point of least information, and live with it for four years. The better question is which one fits the next eighteen months.Organic social vs paid socialThe comparison is usually framed as free versus paid, which is why it produces bad decisions. Both cost money. They just buy completely different things.Google Ads vs Amazon AdsThe difference is not intent or cost per click. It is whether you end up with a customer you can contact again, or a transaction Amazon owns the relationship for.Creator content vs studio productionThe comparison is usually framed as cheap versus expensive, which is why it goes wrong. Compare cost per asset that actually gets used and the gap narrows sharply.In-house studio vs production partnerWhether to build a studio is decided by how many assets you need every month and how predictable that number is — not by how much you care about the work.Native vs cross-platform appsThe technology argument is largely settled and mostly irrelevant. What decides this is how many engineers you have and how close your product sits to the hardware.Attribution vs incrementality testingThese are not competing methods for the same job. They answer different questions, and most measurement arguments are really two people answering different ones at each other.

Services referenced

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