Most build decisions are made on the basis of initial development cost. What the budget rarely captures is the ongoing cost of keeping a custom SharePoint intranet operational and current. Every integration change requires developer involvement. Every role or permission adjustment that was not anticipated in the original architecture requires a code change. Every new office, department, or practice group site requires a build cycle. Every update to the UI, however minor, goes through development, testing, and deployment.  For a mid-sized firm, this ongoing professional services dependency can represent a significant annual spend above and beyond the initial build. The question to ask is not what it costs to launch the intranet, but what it costs to run it for three years.

SharePoint is a capable platform. It is not, by default, an attorney-friendly interface. Out-of-the-box SharePoint surfaces a generalist document and collaboration environment that was not designed around the cognitive patterns of legal work — matter-centric navigation, time-critical billing alerts, role-specific content surfacing, and unified access to DMS, HR, and finance data from a single screen.

Firms that build custom SharePoint intranets typically invest in a change management program to compensate for interface complexity. This adds cost, extends the launch timeline, and rarely solves the underlying adoption problem, which is architectural, not behavioral.

Law firms have fluid organizational structures. Attorneys move between practice groups. Associates become partners. Lateral hires arrive with specific access requirements. Administrative staff change roles. In a well-architected intranet, these changes are handled in minutes by an IT administrator or HR team member — with no development involvement.

In a custom SharePoint build, persona and permission management is typically hardcoded into the architecture. A role change requires a developer to modify the permission model, test the change, and redeploy. In a firm with frequent lateral movement, this creates a persistent administrative backlog and a recurring professional services cost.

Before committing to a custom build, IT teams should prototype the specific persona update workflow they will need to perform regularly, and verify that it does not require developer access to execute.

This is the question that most custom build scopes underestimate. Law firms do not operate from a single data source. Attorneys need to query DMS documents (iManage, NetDocuments), SharePoint content, HR policies, Time and Billing records, and matter data — ideally from a single search interface that understands who is asking and returns results appropriate to their role and access level.

Building this capability from scratch on SharePoint requires significant Azure Cognitive Search configuration, custom indexing pipelines for each integrated system, semantic ranking implementation, and role-aware result filtering. Each of these is a non-trivial engineering effort. Each integration has its own API characteristics, authentication requirements, and data update cadence.

The honest assessment is whether the firm's IT team has the bandwidth and expertise to build, maintain, and extend this capability — or whether an existing, tested integration layer would deliver better outcomes faster.

Microsoft 365 is a continuously evolving platform. SharePoint Online receives regular feature updates. Azure Cognitive Search evolves. The Copilot extensibility framework changes. Power Automate connectors are deprecated and replaced.

In a custom SharePoint build, every significant platform update creates a compatibility assessment requirement. Some updates are absorbed gracefully. Others require rework of custom components, updated API integrations, or regression testing of bespoke functionality. This is not a hypothetical risk — it is a predictable, recurring cost of custom development on a managed cloud platform.

The question is who absorbs that cost and effort: the firm's IT team, or a product vendor whose business model is built on maintaining platform compatibility as a core responsibility.