A calendar becomes less useful when appointments and intended work occupy the same time without an explicit trade. Review the capacity behind the entries before promising another delivery.
Include necessary preparation, travel or transition where those conditions apply. A meeting ending at the same moment another begins may be possible, but only if the practical circumstances support it.
Identify the real commitment
In a fictional working week, a two-hour client session also needs a reviewed example beforehand and follow-up afterwards. Reserving only the visible meeting leaves the supporting effort to compete with promises already made.
Keep optional intentions distinguishable from commitments involving other people. When an agreed slot changes, tell the affected person and update the record. Quietly moving the entry does not renegotiate their expectations.
Review repeated overruns for their cause. The task may need a smaller scope, a different sequence or a more realistic allowance. Use observed effort to improve the next plan. A credible calendar can contain space and uncertainty; what matters is that its commitments mean something dependable when another person relies on them.