How to Build a SaaS Stack Audit
You cannot optimize a stack you cannot see — start with a complete inventory.
The discovery phase
Most companies do not know exactly how many SaaS tools they are paying for. Start your audit by pulling every recurring charge from the last 12 months of credit card and bank statements. Separate individual department purchasing from centralized IT purchasing — shadow IT is real and significant. Cross-reference with an employee survey asking which tools they use weekly. Your starting inventory will almost always reveal tools that no one has ownership of and some that no one remembers purchasing.
Categorize by criticality
Once you have a complete list, assign each tool one of three categories: mission-critical, frequently useful, and rarely used. Mission-critical tools are those whose failure would stop core operations within the day. Frequently useful tools add real value but have alternatives. Rarely used tools are candidates for cancellation regardless of cost. Criticality should be determined by the team that uses the tool, not by the person who purchased it.
Calculate actual per-active-user cost
For each tool, calculate the annual cost divided by the number of monthly active users in the last 90 days. This per-active-user cost is the most honest measure of value. A tool that costs 200 dollars per month with 20 active users costs 10 dollars per user — possibly excellent value. A tool that costs 100 dollars per month with 2 active users costs 50 dollars per user and deserves a harder look. Surface these numbers for leadership, not just the headline subscription costs.
Identify redundancy and consolidation opportunities
Map your stack to see which categories have multiple tools. Two project management tools, three communication platforms, two video conferencing services — redundancy in a stack is not just a cost problem, it is a collaboration problem. People work where they are comfortable, which means context and work product gets scattered. Consolidation often improves both cost and team effectiveness, but it requires honest internal negotiation about which team's preferred tool wins.