I thought I was in OK shape - I swim a little short of a mile a few times a week. Thought I was ready to swim with a group. I saw that the Glemmore Pool had a "Conditioning Swim" at a time that was more convenient to me. I called and found that it was drop in. It was either covered by one's membership with the city pools and recreation centers or one could pay the drop in fee.
My workouts are generally about 3/4s distance and then a bunch of sprints - mostly freestyle and some breaststroke. Well, Carol, the coach, put me eventually in the second fastest lane which I managed to keep up with - mostly. I had to take a few breaks - my legs were killing me - We started with a short warm up and then went to a lot of lengths with legs only - mine were burning.
If you are swimming regularly and want to see how you are doing then I would definitely advise going to one of their workouts. Different times most days of the week. Lanes for most levels of 'in-shapeness".
You can check their schedules here: Glenmore Swim Times
By the way - I loved the workout. I'll be going more often. Thanks Carol.