IaaS, PaaS and SaaS are not technology categories. They are a chart of who gets the phone call when something breaks at 2 a.m. That is the only framing that matters to a 40-person company. The rest is a vendor slide with three stacked boxes.
Who is holding the pager
IaaS is renting virtual machines, disks and networks. Azure, AWS, GCP. The provider owns the hypervisor, the power, the physical disk. Everything above that is yours: OS patching, firewall rules, backups, and the RDP port somebody opened to the internet in 2021. App down at 2 a.m.? You are on the call.
PaaS is handing over a container or a git repo. Azure App Service, Heroku, Render. The provider runs the OS, the runtime, the patching and scaling. A bad database query still wakes you up, but nobody in your company patches a kernel CVE on a Sunday.
SaaS is Microsoft 365, Google Workspace, Salesforce, QuickBooks Online. Someone else runs all of it. You still own accounts, permissions, configuration, and your data. That last one is where the surprises live.
Nobody decided to go SaaS. It happened one card at a time.
Most SMBs treat cloud adoption as a decision ahead of them. It already happened. Marketing bought a scheduling tool. Ops bought a form builder. Someone in finance expensed a transcription app that holds three years of client calls. Nobody kept a list.
The real question is almost never "IaaS or SaaS." It is "can anyone name the several dozen SaaS apps we pay for, who administers each one, and which hold customer data?" Usually the answer is no, which is a security problem long before it is a strategy problem.
The fix is cheap and boring. Pull the enterprise applications and OAuth consent list out of Entra ID or the Google Workspace admin console, then cross-reference a year of card statements. One afternoon. The list runs longer than the guess every time, and usually turns up a tool a departed employee set up under a personal account.
The shared responsibility model, and the part people get wrong
Your SaaS provider guarantees the service. Not your data. Microsoft keeps Exchange Online running and replicates your mailbox so Microsoft can recover from its own failures. That is not a backup you control. Microsoft's own shared responsibility material says as much: your data is your responsibility whichever model you buy.
Recycle bins and retention policies are not backups. Recycle bins empty on a schedule. Retention and legal hold in Purview are compliance tools, not recovery. Neither saves you from a compromised global admin, a sync client that deletes a document library and faithfully replicates the deletion everywhere, or a mailbox wiped when someone reclaimed a departing employee's license.
This is why Veeam Backup for Microsoft 365, Datto SaaS Protection and Backupify are a product category. When a market forms to back up the thing you assumed was already backed up, that is worth a few dollars per user per month and an afternoon of restore testing.
IaaS is oversold, PaaS is misaddressed, hybrid is usually a stalled migration
Renting EC2 to run the VMs you ran badly on-prem does not modernize anything. It relocates the problem and adds an egress bill. Go to IaaS for a specific reason: a vendor who only supports their app on a VM you control, a contract demanding controls no SaaS tenant offers, or a genuinely bursty workload. "The server closet is too hot and the UPS is nine years old" counts too, but that is a facilities problem.
PaaS is good, and mostly irrelevant if you do not employ developers. Two developers and one internal app? App Service or Render will save more of their time than any amount of IaaS network design. Zero developers? PaaS is trivia.
Hybrid is usually not a strategy. It is a migration that stopped halfway because the file server was annoying to move. Fine as a state, bad as an architecture. Deliberate hybrid exists: an imaging modality writing DICOM to a local node at full speed, then replicating off-site. The test is whether someone can give the reason in one sentence without using the word strategy.
Syncritech spends more time inventorying the SaaS a company already bought than moving anything into IaaS, because that is where the risk sits. The imaging version of deliberate hybrid is our Soteria Cloud Archive. Everyone else, start with the list. You cannot pick a cloud model for software you cannot name.
