You should it depending on how long it last. In other words if you have 80% battery life and you only use 20% a day there no need to recharge it. I use my phone a lot were as my wife does not. Wow that's strange. Also you should completely drain your battery each month. This helps with the longevity of the battery.
Charge it whenever you want. iPhones have new batteries that don't have memory cells like the past batteries. Of course you want to have a full battery in morning. You can leave on charger overnight. It has trickle charge tech so it won't overcharge. I still do a battery refresh every month tho.