The question is how does your trainer know how long and how often?
And yes your trainer should know that.
All exercise routines are based on the fitness level and health levels of our clients.
So the rest should also take those factors into consideration and I would also add the following factors :
Season of the year.
Recovery speed from one session to another.
Put all those factors into the mix and then a trainer knows exactly what to do.
Sometimes the rest should be twice a week.
Sometimes once a week and other times every second day.
I have my secrets around it so I always apply it to my clients for better results.
But one thing I say to you, everyone should rest at least once a week.
And when I say rest I mean no exercise and a lot of sleep .
So it is bed time !
Yes you should rest between your workouts.