I don't know how old you DD is, but I think it is certainly beneficial to reduce screentime for all ages (although there are some days when pjs & a morning of kids' tv is called for!)
With my DSes (age 4.9 & 2.5) I try to only turn on the TV after they've had dinner - which they usually finish about 6-6.30pm. They then have it on until bedtime (8pm). In addition to this, DS2 watches a 'Learn to talk' DVD, which is 30 mins long, once a day, to help with his speech, which is very delayed. SALT has agreed that this may be beneficial for him.
I do notice a difference in them when we have more TV, at the weekends or school holidays - they tend to be less cooperative & more whingey.
We try to be outside a lot, either in the garden, at the shops, toddler groups, activities, soft play, parks, playdates, which tbh I think they get more out of anyway.
Good luck with your DD 