Eyelash Extensions: How to Manage Infill Cycles and Patch Tests

Eyelash extensions are an interesting business. The full set is the headline service; the infills are where the actual revenue happens. A studio that books 10 full sets per week and 30 infills makes 4x more on the infills. The software needs to support that pattern.

The infill cadence problem

A full set lasts 3–4 weeks before they need an infill. After 4 weeks, lashes shed faster than they can be replaced — at that point the client needs a new full set, which is more expensive but takes 2x as long.

The window of profitable rebooking is week 2.5 to week 3.5. Miss it, and you've lost an infill ($60–$80 of revenue) and gained a half-empty schedule.

Automated rebooking nudges

The single highest-impact change: automated rebooking SMS at the right interval. Trimsy lets you set per-service rebooking intervals — for "lash full set," set rebook = 18 days. Eighteen days after the appointment, the client gets an SMS:

"Hi Sarah, your lashes are due for an infill — book this week to keep them fresh. [link]"

Most clients book from the SMS without thinking about it. The studio's calendar fills with infills at the right moment.

Patch tests

Most salon insurers require a patch test before the first lash service. The salon's responsibility is to make sure the test was done, ideally documented.

Workflow:

1. New client books a "lash consultation + patch test" service (15 minutes, free or low-cost)
2. Patch test is recorded on the client profile (date, products used)
3. Full set must be 48+ hours after the patch test — Trimsy can enforce this with a service constraint
4. Annual patch test renewal: a year later, the client gets a reminder before their next booking

Skipping this for "regulars" is risky. Reactions can develop after years of safe use; one customer reaction without a documented patch test is a liability problem.

Tracking lash design preferences

Each client has a lash style they like — classic D-curl, hybrid, mega volume — and a typical look (natural, full glam). Recording it on the client record means every artist who sees the file knows what to apply. New artists in the studio onboard 5x faster with proper notes.

Trimsy's per-client notes field is markdown-supported, so you can structure it however your studio likes.

Combo bookings

Lash + brow combos are common. Pricing them as a discounted package (vs the sum of individual services) drives upsells. Trimsy supports combo templates — set up a "Lash + Brow Tint" combo at a 10% discount, the booking page presents it as a single service to the client.

What to skip

• Lash-specific software. Most of it is overpriced and doesn't add functionality beyond a generalist platform.
• Photo-grid Instagram exporters. Instagram already has those built in.
• Complex tier pricing. Volume tiers ("3D, 5D, 7D") are best handled as separate services, not as variants on one service.

The bottom line

The lash business is built on rebooking discipline. Software that nudges at the right moment and respects patch-test compliance pays for itself within the first month. After that, it's pure margin.