DS is 2yo now. He sometimes has quite a lot of TV time and sometimes very little.
We did have a bit of a routine where he watched 20-30 min in the morning (while I got showered) and 20 min of waybuloo in the evening (whilst I ran his bath and got milk, meds, pjs etc ready), plus possibly something during the day.
There are some programmes he loves on when we are usually out so on our stay at home mornings I tend to let him watch more. Also when we've had a very busy time out at toddler group and he needs some zombie time he watches when we get home. It's always clear when he's finished 'slobbing out in front of the TV' and regained some energy because he walks away from teh TV and gets some toys or comes to me to play.
I sometimes think I let him watch too much, then I swing around and think it's fine because he gains so much from the programmes (letters, numbers etc which he is obsessed with) and the cbeebies programmes well produced which (to me) is totally different to violent cartoons. it's nice for example when he watches Mr Maker and is instantly motivated to go making something so we do an activity together.
He also gets TV time with DVDs, dancing and nursery rhymes. He used to just watch them but now he joins in with lots of dances so it's good for physical activity on wet days. I often watch with him so we are both physical together or like I said before it is an instigator for an activity. TV can be very isolating, disconnection from human beings and parents, but doesn't have to be. These days he doesn't watch all the Waybuloo pre-bath time but will play with toys, then we both join in for the yogo part.