Klaviyo hires go wrong in a predictable way: the merchant buys a retainer when they needed an audit, or buys a flow build when the flows were fine and the segmentation was the problem. Diagnose before you buy.
Start with an audit if you don't know what's broken. A Klaviyo audit costs $1,500-$5,000 and takes 1-2 weeks. It tells you whether your problem is flow architecture, segmentation, deliverability, or list quality — four different fixes with four different price tags. Buying a $6,000/month retainer without knowing which one you have is how merchants end up paying twelve months for the wrong work.
Match the specialist to the problem. Flow builders ($1,500-$12,000 per project) fit stores that need the core five flows built or rebuilt. Segmentation and lifecycle strategists ($100-$250/hour) fit stores where flows exist but revenue attribution is stuck. Deliverability specialists ($2,000-$8,000 per engagement) fit stores with falling open rates or inbox placement problems — a genuinely separate skill set from flow building. Migration specialists ($4,000-$20,000) fit moves from Mailchimp, Dotdigital, or Constant Contact. Ongoing management ($1,500-$25,000/month) fits stores where campaigns and testing run weekly.
Check the Klaviyo Partner tier, and know what it does and doesn't tell you. Klaviyo ranks agency partners Bronze, Silver, Gold, and Platinum, with Master as a separate individual certification. Tier reflects volume and revenue influenced through the platform — useful as a floor, but a Platinum agency is not automatically better for your store than a strong solo consultant. Verify claimed tiers in the Klaviyo Partner Directory on klaviyo.com. Non-Partners can be excellent; they just lack the Partner support channel for escalations.
Ask for attribution screenshots, not case study decks. "We built flows for a $10M brand" is not evidence. "Attributed email revenue went from 18% to 32% of total in 90 days" with a Klaviyo dashboard screenshot is. Ask for three, with dates. Any consultant doing real work has these — the ones who don't produce them usually have a reason.
Get the deliverable list in writing before you sign a retainer. A good Klaviyo retainer names what ships each month: flows built or optimised, campaigns sent, A-B tests run, segments created, and the reporting cadence. "Ongoing Klaviyo management" with no deliverable list is billing for presence, not output.