Don't do this unless an app is unresponsive/not working correctly. It will just make apps slower to restart, using more power than it would if left to suspend/un-suspend as it's meant to.
TBC the discussion is around idle battery usage. Presumably, backgrounded apps will contribute to that. FWIW I do notice a difference, especially depending on what apps are open. Whether closing apps increases battery drain during reopening them for intentional activity is a different question.
If it's an iPhone, then iOS will suspend background apps in favor of foreground apps. If your phone is lagging it's almost certainly because the foreground app is resource-intensive.
If the foreground app requires more resources than are available due to background apps, it will suspend background apps to free up those resources.
Apps don't really have much they can do to get around this, assuming you're not jailbreaking or installing local profiles.
Well-built applications will have already saved state with every interaction. When they go to the background they will start unloading unnecessary resources and prepare for possible suspension by saving any additional data. Then when they're suspended, their state is saved to a snapshot that they can load in later so it's as though they never were suspended.
There _is_ more capacity in recent versions of iOS for an app to use background resources, and to start a background process automatically. Still, the system treats background processes with a lower priority and terminates them for using too much power way more aggressively.
What do you mean how can you know? If the app isn't responding, I force-close it. That's all.
>I have 15 apps "in memory", my phone started lagging
I wish I could tell you... I have 60+ apps 'in memory/suspended' always. I only close an app if there's an issue. I restart my phone maybe once a month, usually from a software update.
The only ways I've seen my phone (iPhone 13, so two years old) lag is:
- playing a demanding game and it gets too hot/throttles
- using music via bluetooth + GPS + charging at the same time (gets too hot)
- when opening 15+ new tabs in Safari simultaneously (like a group of bookmarks), weirdly makes the whole iOS UI stutter for a bit.
I'd forgotten, I _do_ have a shortcut that runs late at night to turn off WiFi and enable low-power mode. I've had it for some time now and not thought about it. Another shortcut runs in the early morning to turn the WiFi on and disable low-power mode.
I didn't keep a great log of how the battery handled before that, but it does seem like I have to charge it less than I used to.
I only force close apps when they're clearly stuck.
Have you configured anything like "disable background network activity"?
Do you force close the apps?