Protecting the reversion
The landlord's interest is the reversion, the asset that comes back at lease end. A Schedule of Condition fixes the documented baseline at lease grant, which means the landlord can later evidence what was demised, in what condition, and what the tenant therefore inherited.
Supporting dilapidations recovery
At lease end, the schedule supports, not undermines, the landlord's dilapidations claim. The schedule defines what was let; the claim measures the gap between that and what is yielded up. Without a schedule, the dilapidations surveyor on either side has to construct a baseline retrospectively, which weakens both positions.
Joint vs separately-instructed schedules
A jointly-acknowledged Schedule of Condition, agreed between landlord and tenant surveyors at lease grant, is the gold standard. It removes the prospect of competing baselines at lease end and is harder to challenge in any subsequent negotiation.
Schedules at rent review
At rent review, the documented condition of the demise is sometimes a relevant input, particularly where the lease assumes a hypothetical condition. The Schedule of Condition can be a useful piece of supporting evidence.