Make a 'silencer' for your phone (with a 3.5mm jack)

CaptionCut off the 3.5mm jack from an old pair of earbuds, headphones, speakers, whatever, and attach it to the inside of your purse, bag, backpack, or whatever you use. Now, you can leave your ringer on, and as long as the plug is plugged in, then your phone will not make any noise. when you unplug, it un-silences it.