Not worth it to keep force closing apps all the time. You are basically doing what iOS is already doing for you. iOS freeze the apps so it won't consume battery and memory. It doesn't run exactly as windows or mac.
There are exceptions though, if you have background app refresh, some apps like skype, facebook, twitter, spotify, and all the other kinds of apps drains battery on the background, so you need those forced closed.
The point of multitasking in iOS isn't to actually multitask like we think we do, we are just switching between apps every time to actually do something.