Doors, readers, cardholders, client sessions and integration modules - often several at once, each with its own limit.

Door or reader count is the usual base, sold in tiers rather than one at a time.

Cardholder limits cap how many people can be enrolled. Whether visitors, contractors and deleted-but-retained records count towards it varies and should be asked explicitly.

Client or operator licences limit concurrent administrative sessions, which is easy to under-buy on a site with several reception desks.

Integration connectors are frequently individual items rather than platform features.

Get the full list in writing against the design, at the size the site will eventually reach, not the size it starts at.

Compare subscription against perpetual plus its annual maintenance - not against the perpetual purchase price, which is not a like-for-like figure.

A perpetual licence is owned indefinitely, but staying supported and receiving version upgrades normally requires an annual agreement. Without it, the software still runs and gradually becomes unsupported and unpatched.

Subscription bundles the licence, support and upgrades into one recurring fee, which is predictable and never ends.

Capital versus operating expenditure often decides it inside an organisation independently of the arithmetic.

Over ten years the two frequently land close together, so the deciding factors tend to be budget treatment, upgrade behaviour and exit terms.

Ask what happens to a perpetual licence if maintenance lapses and is later resumed - back-payment is a common and unwelcome condition.

Another licence increment - and if it crosses a tier boundary, potentially a large one.

Tiered pricing means the incremental cost of one door is unpredictable: cheap in the middle of a tier and expensive at its edge.

Ask for the price of the next tier at the design stage, not the price per door.

Some vendors charge a higher rate for licences bought later than for the same licences bought with the original system, which makes buying headroom worthwhile.

Consider whether temporary doors - a construction phase, a seasonal entrance - can be licensed temporarily or whether they permanently consume capacity.

Record the current licensed count and the actual count somewhere visible. Discovering the system is at its limit during a fit-out is a common and avoidable delay.

Usually yes - video, directory synchronisation, intruder, lift and visitor connectors are commonly individual chargeable items.

This is the cost most often missed, because integrations are discussed as capabilities during selection and priced as modules after the decision.

Some are licensed per connected system, some per camera or per door, and some as a flat platform module.

Third-party licences may also be involved - the video system or the lift manufacturer may charge for their side of the interface.

List every integration in the design and get each priced before committing to the platform.

Check version compatibility too. An integration licensed today may require a paid upgrade when either system is next updated.

It depends on the product - and it is a question that should be answered as a contract term rather than as an assurance.

In most well-designed systems the controllers keep enforcing the rules they already hold, so doors work and existing credentials are accepted.

What usually stops is administration: no enrolments, no revocations, no reporting. That is a serious security exposure, because leavers cannot be removed.

Some subscription products disable the management platform outright, and a few restrict controller behaviour.

Data export is the companion question: in what format cardholder records and event history can be extracted, and whether export remains available after a lapse.

Test the export during the contract rather than discovering its limitations at the end.

Sometimes, and the terms vary enough that it matters at a building sale, a refit or a server replacement.

Licences are often tied to a hardware identifier or a software key, so replacing a server can require reissuing them.

Transfer to a different legal entity - when a building or business changes hands - is frequently restricted or chargeable.

Where a system is installed by a landlord and operated by tenants, establish who holds the licence and what happens at lease end.

Ask about reassignment when doors are decommissioned: whether the licence returns to the pool or is simply lost.

Keep the licence documentation with the system records rather than in a purchasing archive. It is the access administrator who will need it.

Annually, against the actual door, reader and cardholder counts - because both over-licensing and hitting a limit unexpectedly cost money.

Systems accumulate. Doors are added, cardholder records are never deleted, and the count drifts upward without anyone tracking it.

A yearly reconciliation catches the limit before a project runs into it, and identifies modules being paid for and not used.

Dormant cardholder records are a common cause of hitting a limit. A retention policy that archives leavers keeps the count honest as well as satisfying data protection obligations.

Review the support agreement at the same time, including the version currently running and how far it is from end of support.

Put the renewal date, the counts and the contract terms in one place. The person who negotiated the original agreement will not always be there.