Previously owned iPhone. Used usb dongle to transfer photos etc. Connected up. Manual said could take several hours. Left for few hours but all happened was old phone fully charged & new s7 battery drained. Tried again later & worked. My question is has this damaged battery? 2nd question while I know everyone's battery usage different when fully charged on settings/device maintenance/battery how many hours estimated battery life should a new s7 have?
Lithium batteries are pretty hardy so No it should not have damaged the battery.
Just try not to let it discharge below 15% often. Some say dont let it charge to 100%
Yes battery usage stats and screen on time is a subjective topic.
Take into account it can take a few discharge / recharge cycles for the phones battery to reach optimum output.
As we all set up our phones differently with different apps, app preferences, different signal connection strengths and have features of the phone that does not interest us turned Off then each phone will be different.
When I used the Samsung Galaxy s7 edge I usually had around 3-4 days between charges.
The s7 has a smaller battery so perhaps as a guess 2-3 days.