Suppose a short rehearsal has an opening, three content sections and a closing. Start when the rehearsal begins and press Lap after each boundary without pausing. The five rows then preserve both each section length and the cumulative elapsed rehearsal time.
Name the boundaries outside the stopwatch
LapWatch intentionally has no free-text labels, so write the section order in your own notes before starting. Lap 1 is the opening, laps 2–4 are the three sections and lap 5 is the closing. This prevents analytics or exported data from receiving presentation content while keeping the numeric mapping reproducible.
Compare segments, not only the final total
After the final lap, compare fastest, slowest and average only as a scan for unusual section lengths. Read the exact table before changing the rehearsal. Export CSV, add section names in your own document, and repeat as a new session if needed. Do not combine rows from different runs without preserving which run they came from.
Know what the browser cannot promise
LapWatch is an informal in-page instrument, not an independent clock service. Closing or reloading the page clears every timestamp and lap. Device sleep, browser suspension and operating-system differences can affect what one browser reports. Keep another suitable method whenever the duration matters, and never use this tool for medical, emergency, food-safety, transport, industrial, official, legal or other safety-critical timing. The fixed 99:59:59.999 and 500-lap limits prevent a forgotten tab from pretending to provide unlimited continuity.