The Apple Watch Series 3 earns a 6 out of 10 on our repairability scale (10 is the easiest to repair):

Watch band replacements remain fast and simple.

Screen replacements are difficult but do-able—it's the first thing to come off, and detaches via simple ZIF connectors.

Battery replacements are tricky but fairly straightforward once you're inside, provided you're armed with a Y000 screwdriver.

While not proprietary, incredibly tiny tri-point screws are a repair hinderance.

Replacing any of the component cables requires microsoldering.

The mostly resin-encased S3 system makes most board-level repairs impossible.