The cadence ceiling
Maximum 4 SMS per month to the main list. Beyond that, opt-outs spike and it costs more than it earns. VIP segments can handle 6–8, but only because they self-selected in.
Content that works
Short, conversational, and useful. 'Hey — flash sale, just 4 hours' works. '🎉 FLASH SALE!! SHOP NOW 🔥🔥🔥' doesn't. Consumers read SMS the way they read texts from friends.
Opt-in structure
Double opt-in at checkout, post-purchase confirmation, and clear unsub instructions in every message. Compliance isn't optional — TCPA lawsuits are real.
SMS as a retention tool, not acquisition
SMS works best for people who already know you. Trying to acquire via SMS is an uphill battle that rarely pays back.