Do you need to quickly capture action items before you can put them in a proper task manager?
Do I have to install the watchOS app?
Can I install the watchOS app without the iOS app?
Do the iOS and watchOS apps sync data?
Yes. Triage uses iCloud CloudKit databases, all of your triage items will be synced between your iPhone, iPad, Apple Watch and Mac.
Is this a full todo app?
No, and it isn't trying to be one. Triage helps you to quickly capture things you'll otherwise forget to put in your big, fancy todo/task tracker.