Garmin Forerunner245 vs. 645
A newer model and all-around solid watch for more serious runners.
Reasons to Pick the FR245
LONGER BATTERY LIFE
The 245 has 24 hrs of battery life on GPS vs. the 14 hrs of the 645.
Creates a pacing plan for your races and runs, based on elevation and goal time.
An older but higher-end model with more tracking profiles and an altimeter. Greatly discounted on 3rd-party retail sites.
Reasons to Pick the FR645
Make contactless payments using your watch.
Also tracks Skiing, Snowboarding, XC Skiing, Paddleboarding, Rowing, Stairs Climbed.
Learn more in my in-depth comparison.