Jumperoo fan here, but agree, 20 or so mins per day is more than plenty!! DS loved it, he would shriek with delight - we tried him in it at the shops before purchasing

However after having a child with Hip Dysplasia though - orthopedic surgeons think items like jumperoos, jolly jumpers and baby walkers have A LOT to answer for, if used too much they definitely interfere with normal growth and development of muscles, balance and even bone growth!! Definitely in moderation!! They are definitely more beneficial to parents to amuse and distract bubs so we can have a shower or get a quick task done that having a meaningful impact on your babies development