Shorts 100%, when training or not, except to go to work, when climatic conditions require, and for the rare formal occasion.
"Formal," to me, means I have to wear long pants.
Since during the school year, I do a lot of my training in short minisessions during breaks throughout the day in my office, I wear pants I can train in (usually some form of "tactical" cargo pants with some stretch in the fabric). Thankfully, this is acceptable at my job.
I did have a blowout once in the past when I was training at work in regular khakis. I got some duct tape from a custodian, went in the bathroom, took the pants off and patched them from the inside, put them back on, and went about the rest of my day. Either no one noticed, or if they did, they were too polite to mention it.