I pretty much don't turn on WiFi unless I'm doing streaming audio or video.

Having wifi on is pretty bad for my battery life in general, because I'm moving around a dense city and my phone constantly is trying to connect to open wifi hotspots that are going in and out of range. Keeping it on only extends battery life if my phone is staying in one place with good wifi.

As a general rule, I always turn off the prompt to join open networks. At best, it's annoying as you move around; at worst, you accidentally join a malicious open network.

Settings > Wi-Fi > Ask to Join Networks (at the bottom of that screen)

Here are the options:

Airplane mode, Wifi only, Mobile data (LTE) only, Wifi + Mobile data (LTE). This listing is in order of battery consumption AFAIK.

The user I responded to uses only Mobile data (LTE). His Wifi is never on, but his Mobile data always is. I suggested that since he uses mobile data instead of wifi, he would be using more battery.

When using WiFi your cell radio is still on. The only time having wifi off has been a detriment to my battery is in crappy cell coverage.

Your cell radio is only still on if you leave it on. I've spent plenty of time in airplane mode with wifi enabled for battery reasons.