I work out at a city rec center, largely because the price - about $10/month - is hard to beat.
Schedule consistency is a downside, however. Due to events and maintenance I’ve sometimes shown up to find my location unexpectedly closed.
After some research, I found that the city does a pretty good job of posting schedule changes online. But, since there’s no way to subscribe to them, you need to check every time before visiting.
So, I built NYC Park Alerts. It lets you subscribe to locations of your choice, and will email you when updates are posted. Go sign up at parks.simon.codes if you’re also a rec center fan!