The First 90 Days Set the Foundation for Everything That Follows
If you have recently signed a contract with a CMMC consulting firm—or are seriously considering it—one of the first questions you are likely asking is: what actually happens once we get started? That is a fair question, and the honest answer is that the first 90 days of a well-structured engagement are the most critical period of the entire compliance journey.
At Cleared Systems, we have guided dozens of defense contractors, subcontractors, and suppliers through this process. What we have learned is that organizations that understand what to expect up front move faster, waste less money, and arrive at their C3PAO assessment far better prepared than those that walk in blind. This post breaks down how a structured CMMC consulting engagement should unfold across three distinct phases—roughly 30 days each—and what your team should be doing at every stage.
Before we dive in, it is worth noting that the scope and intensity of your engagement will vary depending on your CMMC level. If you are not yet certain which level applies to you, our post on CMMC 2.0 Level 2 is a good starting point, and our CMMC, CUI & DFARS compliance services page outlines the full range of support we provide.
Days 1–30: Discovery, Scoping, and the Gap Assessment
The first month of any credible CMMC consulting engagement is almost entirely focused on understanding where you stand today. Do not let anyone rush past this phase. Skipping or shortchanging discovery is one of the most common—and costly—mistakes defense contractors make when they try to accelerate their path to certification.
Kickoff and Stakeholder Alignment
Your engagement should begin with a formal kickoff meeting that brings together your compliance manager, IT leadership, legal or contracts team, and your consulting team. The goal is alignment: everyone needs to agree on scope, timelines, points of contact, and documentation access. Be prepared to share your current contracts, any existing security documentation, network diagrams, and system inventories.
This is also the moment to define your Controlled Unclassified Information (CUI) environment. If you are unsure how CUI flows through your organization, our resource on Controlled Unclassified Information provides essential background. Scoping your CUI boundary incorrectly at this stage creates problems that compound through every subsequent phase.
The Gap Assessment
The gap assessment is the cornerstone of the first 30 days. Your consulting team will evaluate your current security posture against the 110 practices in NIST SP 800-171 and the corresponding CMMC Level 2 requirements. This includes:
- Reviewing existing policies, procedures, and security documentation
- Interviewing key personnel across IT, operations, HR, and management
- Examining technical controls across your network, endpoints, access management, and cloud environments
- Identifying gaps between your current state and required controls
- Calculating an initial Supplier Performance Risk System (SPRS) score
By the end of day 30, you should have a clear, written gap analysis report in hand. If your consulting partner cannot produce this document, that is a significant red flag. For a deeper look at what this assessment entails, our post on NIST SP 800-171 assessment templates is a useful reference.
Days 31–60: Remediation Planning and Documentation Development
With the gap assessment complete, the second month shifts to planning and building. This is where the real work begins—and where many organizations underestimate the effort required.
Developing Your System Security Plan
The System Security Plan (SSP) is a required artifact for CMMC Level 2 assessment. It documents how your organization implements each of the 110 NIST SP 800-171 controls. Your consulting team should work closely with your staff to draft and review this document—it cannot be a generic template dropped on your desk. Our post on SSP and POA&M as critical components of a strong security program explains why these documents are so foundational.
Building Your Plan of Action and Milestones
No organization enters a CMMC engagement fully compliant. The Plan of Action and Milestones (POA&M) captures every gap identified in the assessment, assigns ownership, establishes realistic remediation timelines, and tracks progress. A well-structured POA&M is not a list of problems—it is an active management tool. Assessors will scrutinize it, so it needs to be honest, current, and defensible.
Policy and Procedure Development
Most small and mid-sized defense contractors reach this stage with either outdated policies or none at all. Expect your consulting team to help draft or revise core documentation including:
- Access control and identity management policies
- Incident response plans
- Configuration management procedures
- Media protection and physical security policies
- CUI handling and marking guidelines
This documentation work is not bureaucratic box-checking. Assessors will test whether your people actually follow these policies, so they need to reflect real operational practice. Our compliance program development services are specifically designed to help organizations build documentation that holds up under scrutiny.
Technical Remediation Begins
Alongside documentation, your IT team—guided by your consulting partner—should begin closing high-priority technical gaps. Common priorities in this phase include multi-factor authentication, audit logging, endpoint protection, and encryption for CUI at rest and in transit. For organizations evaluating cloud environment requirements, our post on GCC High for ITAR and CMMC 2.0 addresses one of the most frequently asked infrastructure questions we receive.
Days 61–90: Readiness Validation and Mock Assessment
The third month is about validation. You have done the planning and begun the remediation work. Now it is time to test your posture before a C3PAO assessor does.
Internal Readiness Review
Your consulting team should conduct a structured internal review that mirrors the actual CMMC assessment process as closely as possible. This includes document review, technical testing, and personnel interviews. The goal is to surface any remaining gaps—particularly those that are easy to miss in daily operations but will be immediately visible to an experienced assessor.
Mock Assessment
A mock assessment is one of the highest-value activities in the entire engagement. Think of it as a dress rehearsal. Your team walks through the same evidence-gathering and interview process they will face during the real assessment. This exercise serves two critical purposes: it identifies late-stage gaps that can still be addressed before the formal assessment, and it builds confidence and familiarity among your staff so they are not caught off guard. Our detailed post on how to prepare for your CMMC audit is worth reviewing before this phase begins.
SPRS Score Submission and Next Steps
If you have not already submitted your SPRS score to the DoD's Supplier Performance Risk System, your consultant should help you do so before the engagement closes out. Your score must reflect your current, documented posture—not an aspirational one. From here, your roadmap to formal C3PAO assessment should be clearly defined, with remaining remediation items tracked and owned.
What Makes a CMMC Consulting Engagement Succeed or Fail
After working through this process with many contractors, a few patterns consistently separate successful engagements from frustrating ones.
Factors That Drive Success
- Executive sponsorship: When leadership treats CMMC as a business priority—not just an IT project—resources and decisions move faster.
- Honest gap disclosure: Organizations that share complete, accurate information with their consulting team get better results. Your consultant cannot fix what they cannot see.
- Dedicated internal resources: CMMC compliance requires real time from your staff. Plan for it in advance.
- Realistic timelines: Most organizations need six to twelve months from engagement kickoff to assessment readiness. The first 90 days build the foundation—they are not the finish line.
Common Pitfalls to Avoid
- Treating the SSP as a one-time document rather than a living record
- Underestimating the scope of your CUI environment
- Deferring technical remediation until the final weeks before assessment
- Selecting a consulting partner without verifying their CMMC-AB registration status
If you are still evaluating consulting partners, our post on how to evaluate a CMMC consulting partner before signing a contract provides a practical framework for that decision. And for organizations operating in the defense industrial base who want ongoing security leadership support beyond the initial engagement, our regulatory vCISO services provide fractional CISO support calibrated to your compliance obligations.
Ready to Start Your CMMC Compliance Journey?
The first 90 days of a CMMC consulting engagement are not a sprint to certification—they are the deliberate, structured work of understanding your environment, building your documentation, and closing your most critical gaps. Organizations that approach this phase with discipline and the right partner consistently outperform those that treat it as a checkbox exercise. If you are ready to get started or want to understand what an engagement with Cleared Systems would look like for your organization, request a quote today and let us build a roadmap tailored to where you are right now.