Every time a cross-sell requires a custom scope, a new proposal, and a separate contracting process, most of the opportunities die before they start. The client’s need was real. The timing was right. But the friction of turning that need into a billable engagement, the back-and-forth, the scoping call, the proposal writing, adds enough drag that the conversation gets deprioritized and eventually dropped.
A pre-defined add-on library removes every step between “client has a need” and “client approves the work.” The scope is already written. The price is already set. The deliverable is already named. The only question is yes or no.
This is not about oversimplifying complex work. It is about identifying the work that is genuinely repeatable, the adjacent services you provide more than twice a year, and packaging them so that selling them costs you nothing but a single sentence.
What Makes a Good Add-On
Not every service can become an add-on. The right candidates have three characteristics.
Repeatable delivery. You have done this type of work at least three times. You know what it takes, what goes wrong, and how long it actually takes. If a service requires a novel approach every time, it cannot have a fixed scope, and a scope that varies means a price that varies, which kills the “just add it” dynamic.
Bounded scope. The deliverable has a clear end state. “Email newsletter setup” is boundable, it ends when the tool is configured, templates are built, and the first three issues are drafted. “Ongoing strategy” is not, there is no natural endpoint. Unbounded services are retainers, not add-ons.
Relevant to adjacent problems. The add-on should solve a problem that commonly appears alongside your core service. If you do SEO content, an “existing content audit” is relevant, clients asking for new content often have old content that needs updating first. If you do brand identity, “brand application to social templates” is adjacent, clients who have a new brand need it applied somewhere.
Building the Library: Structure and Examples
Each entry in your library has four parts:
- Name: Specific outcome, not service type. “30-Day Launch Sequence” not “Email Marketing.”
- One-paragraph description: Problem it solves, what’s included, what’s excluded, and outcome the client can expect.
- Price: Fixed. Non-negotiable unless scope changes.
- Timeline: How long delivery takes once the add-on starts.
Here are five examples across different service types:
SEO consultant add-on:
Name: Historical Content Audit Description: For clients who have been producing content for 12+ months and want to understand which pieces can be updated to rank rather than starting fresh. Covers a review of 50 pages, a prioritized list of 10 pages worth updating, and a brief for each update. Excludes implementation. Price: $1,800. Timeline: 10 business days.
Brand/visual consultant add-on:
Name: Social Template Kit Description: For clients who have completed a brand identity and need production-ready templates for LinkedIn, Instagram, and email. Delivers 12 templates (4 per platform), a usage guide, and one round of revisions. Excludes ongoing content creation. Price: $2,200. Timeline: 7 business days.
Business consultant add-on:
Name: 90-Day Roadmap Sprint Description: For clients at a decision point who need clarity on priorities. One 2-hour working session, a written roadmap with three initiatives ranked by impact and effort, and a 30-minute follow-up call at 60 days. Excludes implementation. Price: $2,500. Timeline: 5 business days from workshop.
Copywriter add-on:
Name: Competitor Messaging Audit Description: For clients launching a new page, campaign, or positioning update who want to know how their current messaging compares to 5 direct competitors. Delivers a one-page audit with gap analysis and three specific positioning recommendations. Price: $1,200. Timeline: 5 business days.
Developer add-on:
Name: Performance Diagnostic Description: For clients experiencing slow load times or conversion drops on an existing site. Covers Lighthouse audit, core web vitals analysis, prioritized list of 5 fixes with estimated impact, and a 30-minute call to walk through findings. Excludes implementation. Price: $1,500. Timeline: 3 business days.
The “Excludes implementation” language in most of these descriptions is deliberate. It keeps the add-on bounded. If the client wants to implement after the audit, that is a new scope conversation, typically at a higher price.
Pre-defined add-ons shift the cross-sell from a proposal process to a simple question. When the scope is already written and the price is already set, the only thing between the client’s need and your revenue is the sentence: “This looks like a [Add-on Name] situation, want me to add it?” That sentence takes four seconds to say. The alternative takes a week of back-and-forth.
Where to Put the Library
Three places, with different purposes.
1. Client workspace (Notion, Google Drive, or your portal). Create a page called “Additional Services” with all add-ons listed. Clients browse it on their own when they have a need and want to see if you already have something. This generates passive inbound, clients who self-identify a need and ask about the add-on without you having to introduce it.
2. Proposals. After the main proposal scope, include a section called “Optional Add-Ons” with 2–3 relevant items from your library. Clients reviewing a proposal are already in buying mode, they are more likely to add something on than they would be in any other context.
3. Monthly check-in agenda. Reserve 3–5 minutes at the end of every monthly check-in for a brief scan: “Looking at the library, anything here that’s relevant to what you mentioned about [specific thing from the conversation]?” This is not a sales pitch, it is a structured check that happens every time, which normalizes it.
The Introduction Script
When a client mentions a problem that maps to an add-on, use this:
“That’s actually something we have a defined process for. It’s called [Name], the short version is [one sentence description]. It’s $[X] and takes [timeline]. Want me to add it to the current engagement, or should I send you the full description to review?”
Two options again. Either they agree now, or you send them the written description (the one-paragraph description from your library). Both move forward.
Do not scope it live. Do not negotiate the price live. The fixed scope and fixed price are the product. Changing them in the moment turns the add-on back into a custom project.
Maintaining the Library
Review the library twice a year. Add add-ons based on services you’ve delivered more than twice in the past six months. Remove add-ons you’ve offered but no client has purchased in 12 months, either the need isn’t real, the price is wrong, or the description isn’t communicating value.
Revise descriptions when you get questions. If a client asks “what does that include?” it means the description isn’t specific enough. Tighten it until the question stops.
The library is living documentation of your most repeatable adjacent value. Its real function is not the document itself, it is forcing you to identify, name, and price the work that was previously invisible revenue sitting undiscovered in your existing client relationships.
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