i’m running the NYC marathon soon and am wondering how folks have used their watches in world major marathons (i.e., highly dense, tall building obstruction).

i was planning on tracking from workouts, but also have strava.

i figure GPS will be unreliable, but is it worth it to try and manually lap each mile (only on workouts, not on strava), or basically just use it as a fancy stopwatch that can give some stats on HR and rough estimates of pace?

fwiw, i have a series 8, so don’t have a dedicated button to lap and would need to double tap.

any other tips?