Wi-Fi

New to smart Phone ownership when should I turn on or off the Wi-Fi feature on my phone

In general, you should leave it on all the time. If your phone detects a known network (like at your house), it will connect to the network automatically after you've logged in for the first time. If it can't find a network, it will automatically switch over to your data plan. If you don't have a data plan, you won't have a network connection. In this situation, you may want to turn off your wi-fi to preserve battery life, but otherwise there's no harm in leaving wi-fi on.

Note that if you use WiFi in public places (library, doctor's offices, hotspots, etc.), your connection is not secured. So, to be safe, don't transmit sensitive information under those circumstances.

I turn off the "ask to join networks" feature because it is so annoying and useless to me. It pops up a question about networks I have never connected to. I don't want to connect to them that way. I want to connect to them deliberately.

I turn off my wifi when I am streaming radio (with the TuneIn app) and going in and out of wifi range, because crossing the border causes the phone to reconnect, and it doesn't pick up where it left off.

Turn off wifi when you know you won't encounter it and battery capacity is precious.