What's a good iOS app for keeping track of fitness classes and on-demand workouts, especially when my schedule is all over the place?

Honestly, I've been quite pleased with Life Time Digital. I've figured out three new features this week alone! The categorization system is brilliant; I can filter by class type, instructor, and even equipment needed. It's made scheduling my fitness classes so much easier, especially with my book club meetings and volunteer work at the historical society. And who knew my phone could do this? The on-demand library is a lifesaver when I can't make it to the club. It’s like having a personal trainer available at any hour. The app even lets me add classes directly to my Google Calendar, although I did read a review that mentioned that feature wasn't working for someone. I do hope they fix that soon! Still, it's a delightfully intuitive way to manage my fitness schedule.