What business IT infrastructure looks like

“IT infrastructure” can mean one Wi-Fi router or a global network of data centres. Midsize businesses sit in between. Here are the parts, three worked examples and budget benchmarks.

The parts

Every business has the same six parts. Only the scale changes.

Part	What it includes
Network	Switches, routers, firewalls, Wi-Fi, internet lines and VPN or zero-trust access
Compute	Cloud servers on AWS, Azure or Google Cloud, on-site servers, virtual desktops and laptops
Storage	SharePoint, Google Drive or Dropbox, NAS, SAN, backups and archives
Security	EDR, email security, identity and MFA, SIEM, vulnerability scans and patching
Communication	Microsoft 365 or Google Workspace, VoIP phones, video calls and chat
Management	Remote monitoring and management (RMM), ticketing, documents and asset tracking

The network matters most, since every employee and app depends on it. Compute has moved toward the cloud for a decade, but many firms still run some servers on site.

Three examples

25 employees

A professional services firm with one Manhattan office and standard business apps.

• Network. 500 Mbps fiber with LTE failover and a unified threat management (UTM) firewall. One or two Wi-Fi access points and a managed switch.
• Compute. No on-site servers, with everything in the cloud. Windows and Mac laptops, and one or two meeting room screens.
• Storage. SharePoint and OneDrive for all files. A separate backup of Microsoft 365 data, often missed, since Microsoft does not fully back it up.
• Security. EDR from CrowdStrike, SentinelOne or Defender for Business. Microsoft 365 email security, phishing simulations, MFA through Entra ID and automated patching.
• Communication. Microsoft 365 email, calendar and Teams, Zoom or Teams video, and cloud VoIP with 10 to 15 lines.

It typically costs $60,000 to $100,000 a year with managed services, licences and hardware refresh. That is $2,400 to $4,000 per employee.

75 employees

A financial services firm with offices in Midtown and Jersey City. It has compliance duties and a mix of cloud and older apps.

• Network. 1 Gbps fiber at each site with failover, and firewalls joined by site-to-site VPN. Several access points per floor, with separate guest Wi-Fi, and switches with VLANs by department.
• Compute. Two small servers, one for an old business app and one for Active Directory linked to Azure AD. Azure for newer apps, encrypted standard laptops and Teams or Zoom Rooms.
• Storage. SharePoint and OneDrive, a NAS for large and older files, and backup of cloud and on-site data with offsite copies. Archives hold the seven years compliance requires.
• Security. Central EDR, an email security gateway and a SIEM or MDR service watching around the clock. Yearly penetration tests, quarterly scans, privileged access management and staff training.
• Communication. Microsoft 365 E3 or E5, Teams Phone with direct routing and meeting room hardware at both sites.

It typically costs $225,000 to $375,000 a year, or $3,000 to $5,000 per employee. Two sites and compliance add cost.

200 employees

A healthcare organisation with three NYC-area sites, HIPAA duties and clinical and office systems.

• Network. Redundant internet at each site with SD-WAN, and firewalls with intrusion prevention. Central Wi-Fi with network access control, and clinical systems separated from office and guest traffic.
• Compute. Servers in a small data centre or colocation for the EHR and clinical systems. Azure or AWS for office apps. Virtual desktops for clinical workstations, and standard hardware set up automatically.
• Storage. File sharing for office staff and fast storage for clinical databases and imaging. HIPAA-compliant encrypted backup with tested recovery, and hot, warm and cold tiers managed automatically.
• Security. A SIEM with a 24/7 security operations centre, EDR on every device and network detection for attackers moving inside. Data loss prevention for patient and personal data, and yearly risk assessments and penetration tests under HIPAA. A vendor risk program and an incident plan with tabletop exercises.
• Communication. Microsoft 365 E5 with advanced compliance, a call centre for scheduling and HIPAA-compliant clinical messaging.

It typically costs $700,000 to $1,200,000 a year, or $3,500 to $6,000 per employee. HIPAA and clinical systems push it up.

Cloud, on-site or hybrid

For most midsize businesses, the answer is hybrid.

Best in the cloud	Still on site
Email and collaboration	Old apps too costly to move
CRM and business apps such as Salesforce, HubSpot and NetSuite	Workloads that need very low latency
File storage and sharing	Rules that demand physical control of data
Backup and disaster recovery	Very large local files, such as media, engineering files and imaging
New app development

Hybrid estates join the two with secure networking, one identity system and the same security rules. Most firms of 75 or more that SBK works with run hybrid, though the long-term trend is toward the cloud. Our cloud migration work helps decide what to move, and when.

Budget benchmarks

Company size	IT spend per employee each year	Total IT budget each year
25 employees	$2,400 to $4,000	$60,000 to $100,000
75 employees	$3,000 to $5,000	$225,000 to $375,000
200 employees	$3,500 to $6,000	$700,000 to $1,200,000

These cover infrastructure, support, licences and projects, from industry data and our own experience. NYC runs above national averages, and regulated industries sit at the top.

Spending well below these ranges usually builds technical debt that costs more later. Spending well above them suggests savings in licences, vendors or design.

Your roadmap

1. Record what you have today.
2. Compare it with the benchmark for your size and industry.
3. List projects, riskiest gaps first.
4. Forecast the budget for three years, with quarterly milestones.
5. Set a refresh schedule for hardware and software.

Questions people ask

What matters most for a small business?

A reliable, secure network. Start with a business firewall, internet with failover, endpoint protection and MFA everywhere, and build from there.

How often should we replace hardware?

Laptops and servers last three to five years, and network gear five to seven. Cloud removes refresh cycles for its workloads. Plan refreshes instead of waiting for failures.

Is cloud cheaper than on-site?

Cloud cuts upfront spending and scales well. For steady workloads, monthly costs can exceed on-site costs over time. The real savings come from less management, built-in redundancy and flexible scale.

Is our infrastructure out of date?

Look for frequent outages, slow apps and unsupported security tools. Poor remote work and audit findings are signs too. If staff work around IT, it needs investment.

AWS, Azure or Google Cloud?

Follow your suite. Azure fits Microsoft 365, and Google Cloud fits Google Workspace. AWS is the broadest but harder to learn, and many firms already use a mix.