As a baby, my brother didn't sleep, from 3 months to 2.5 years, all he gave mum was 20 minutes each day/night. To keep her sanity, she would put him in the jolly jumper for ages and ages, trying to wear him out. He's now nearly 30 and has no effects from it.

We put DD in hers, after she got the all clear from hip dysplacia, for short amounts of time, and she loved it. Even when she was in her brace, we would pop her in it, she wouldn't bounce but she liked turning around in it and being upright.