MT5 server hosting you can plan around.
Hosting is the part of a brokerage nobody notices until it fails. For MT5, the questions are about location, monitoring, backups, patching and who is on call when something goes wrong.

Location and latency
Servers closer to your liquidity and your clients can improve the experience, but the right region depends on both. Ask where the servers sit, what connectivity exists to your liquidity providers, and how you can measure the difference rather than rely on a claim.
Monitoring and response
Ask what is monitored, how alerts reach a person and how quickly someone responds. A service level in writing is more useful than an adjective. Clarify what counts as downtime and what remedy applies.

Backups, patches and change control
Platform updates, security patches and plugin changes should follow an agreed process with a rollback plan. Know who may change the server, how changes are tested, and how restores are verified.
Planning for growth and incidents
Review capacity every quarter against client numbers and plugin load, and agree in advance how to scale. Write a short incident plan: who is called, what clients are told and how the cause is recorded. Rehearse it once; the first real incident is a poor time to learn the process.
Questions we hear
Do I need dedicated servers?
It depends on load, plugins and your risk tolerance. Start from your expected client numbers and ask for a sizing rationale.
Who owns the server access?
Agree this at the start. You should know who holds administrator credentials and how access is audited.