I usually turn on my cellphone Mobile Data & WIFI all the time because I don't want to miss SMS and Emails. I'm afraid the battery could lose capacity over time if I keep turning on the Mobile Data/WiFi all the time or something might happen to my mobile. However, I believe modern electronics should be able to handle this kind of scenario. Does this apply to modern Android phones? Or do I need to continue disconnecting and connect only when needed?
Note: I have an unlimited mobile pack.
It all depends on your usage requirements
If you can't afford to miss mails or messages your wifi /data will be on and that will certainly lead to battery degradation. See Battery capacity wear-down, and its relationship to charging practices, specifically the graph and it's explanation.
Turning wifi /mobile data on/off isn't harmful. You can do that if you can live with missing messages or mails.
If your device is rooted you can prevent battery degradation by making the device run from mains as explained here Don't charge the battery but use connected power to run the phone or at least keep the battery charged and discharged within safe limits as explained here Ideal charging / discharging percentage for maximum battery life?
If you don't want to root your battery, your battery will lose its life quickly and you would end up changing the battery or the device. Unfortunately, that's true.
