Predictable pricing, line by line
Every charge should be on the contract. Per-user, per-device, per-site, per-mailbox — plus the rates for the work that's outside the recurring scope (project work, hardware, after-hours). If a number can change without your sign-off, that's not flat pricing. That's discretion you've handed to your provider.
Tools you can name (and check)
Ask which EDR, which backup product, which email-security platform, which RMM. Real MSPs use named, category-leading tools. "Proprietary platform" usually means a thin wrapper around the same tools — at a markup. Names you can search are names you can compare.
An offboarding clause you can read in five minutes
Read the part of the contract that explains what happens when you leave. If it's vague, the goodbye will be expensive. The right MSP commits in writing to handing back configurations, recovery keys, and documentation — at no charge — within a fixed window.
A response SLA in the contract, not the brochure
First-response time, onsite response time, after-hours coverage, and what counts as a P1 should all be in the agreement, not on the website. "Within one business hour" is meaningful; "as soon as possible" isn't a commitment.
A real conversation with the technician, not a salesperson
Before you sign, ask to talk to the engineer who'll be on your account. The salesperson's job is to close. The engineer's job is to keep your network running. The longer that conversation lasts comfortably, the better the fit.