Regarding widgets: widgets that constantly update will obviously drain your battery.
The widgets I use do not. I don't get the point of Facebook/Twitter/Instagram widgets....just go to the freaking app. I think they even have apps now that will put all your social media in one place...so just go to that app.
The widgets I use perform tasks....toggle Wi-Fi, toggle hotspot, toggle led flashlight, etc. The only updating widget I use is a weather widget. I set that to update something like every four hours, cuz that level of granularity is more than enough