Some timing questions are safety requirements
A generic duration estimate should not replace instructions where timing controls safety, structural performance, chemical handling, food safety, medication, medical care, emergency response, hazardous work or regulated procedures. In those cases, use the authority responsible for the specific situation.
This site intentionally avoids calculators that invent those critical durations. A planning calculator may accept an authoritative wait or interval as an input, but it should not manufacture the underlying requirement.
Local and product-specific rules vary
Building permits, inspections, workplace rules, product instructions and service procedures can vary by jurisdiction, manufacturer, model and application. A universally stated number can therefore be wrong even when it sounds plausible.
When the consequence of being early or late could include injury, damage, non-compliance or loss of warranty, verify the applicable instruction rather than optimizing the schedule around an online estimate.
Use calculators for planning, not permission
A calculator can help organize time once the safe or required constraints are known. It cannot authorize work, certify competence, determine code compliance or override a manufacturer or qualified professional.