I'm guessing you are worried about hurting the battery...
Don't be. Those days are long behind us, by at least a decade, if you are using quality products/batteries. I suppose if you buy some cheap battery pack or cheap consumer device you can be concerned. But anymore main brand consumer electronics are just fine.
Apple products have built in overcharge protection, so charge away. And no need to discharge first, etc.
Is it safe to keep the Apple Watch on the charger every night?