The Apple Watch Series 5 earns a 6 out of 10 on our repairability scale (10 is the easiest to repair):

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

Battery replacements are pretty straightforward, once you're inside.

Still a lot of incredibly tiny tri-point screws are used throughout the watch.

Several component flex cables are mounted directly to the S5 package, requiring skilled microsoldering to replace.