The summary.
BEFORE SPENDING ON CAPACITY
Establish what is actually consuming it, and whether equipment is simply old.
Equipment several years old struggles with modern device counts, and replacement frequently resolves what looks like a capacity problem.
Never buy more bandwidth to fix a wireless problem.
WHEN MOVING PREMISES
Order connectivity as early as possible. Installation takes far longer than people allow.
Arrange overlap between old and new so you are never without service.
WHEN CHANGING PROVIDERS
Your public address will probably change. Identify everything restricted to it before switching.
Keep the old service until the new one is proven.
WHEN CABLING ANYTHING
Run more than you need. Cable is cheap during a fit-out and expensive afterwards.
Specify more switch ports than you need.
AUDIT ANNUALLY
You will find devices nobody recognises, configuration nobody remembers, and exposures nobody intended.
Identify before removing. Something may depend on it.
ON IPV6
Little to do for now, but ensure your firewall covers both. A rule set covering only the older protocol leaves a gap.
