We offer one-hour sessions Monday and Tuesday nights after closing, and require that the staff go to one each week. Each week will cover one or two topics.
I have a decent sized staff, about 80 people certified, and one advantage of doing two nights back-to-back is that it is very easy to convey the same information to so many people on two consecutive nights- this keeps everyone on the same page.
A downside to this is that some staff have recurring commitments every Monday and Tuesday- another job, athletics, etc- and they must schedule a "make-up" with an instructor. Also, we are at the mercy of the weather; especially last year due to the rain and cool temperatures in the Midwest, we had to go indoors and do dry activities a lot.
Are there any facilities that conduct in-service trainings while open for the day?
The majority of our in-service training takes place during normal hours. The guards know that at some time during one of their breaks they are responsible to complete one of the requirements for the week. We have found that this works well for us and help reduce payroll by not have all of the guards come when they would normally be off. It is also easier to get them to do the in-service if they are already at work.
This is similar to the route that our program takes. We schedule the staff in for a 30 minute skill in-service before or after each of their scheduled shifts. We run a year-round water park with about ~150 certified staff at this time of year. This may not be feasible with the budget constraints of your program but we have found that scheduling the in-service time during their scheduled shift has made it easier for them to keep up with the skills. This also ensures that the 1 day a week staff member gets at least 30 minutes of in-service training a week. Food for thought.