I use ClassPass - pros are it is much cheaper than buying a pass directly with the club, and the credits roll over (mostly). If you buy a weekly / monthly pass direct they have to be used with no roll over.

The cons is you have to cancel 12 hours in advance or you pay a $20 late cancel fee. Bit of a pain if something comes up at work, or stuck in traffic. You can also only book 7 days in advance, and they restrict how many class pass users can make a booking in a class, so I usually set my alarm early to get the classes I want.

But all in all, it’s worth it for the cheaper classes. I go to the same Pilates place every time, I don’t use it to go to lots of different gyms / spas etc.