TBH I prefer that amount to be zero, but unfortunately his grandfather opened the door for him a year ago. I will for sure not increase his TV time until he is well into primary school, when we won't have much control anyway. The school will show plenty of videos and his friends' parents probably won't be as against screen time as we do. But definitely he is not to own a mobile or pad until he has to -- most likely from middle school.
Both of us follow a sedant life style. We prefer to stay at home. I plan to change this and introduce hiking and camping into our life. Naturally one does not watch TV while hiking or camping, so I'll increase the reading time. This also may lead to star gazing and fossil collecting. My wife is particularly not interested in outdoor activities so it's probably going to be just me and him -- well till I know how to setup a tent at least.
There are other kids that won't see a computer until the age of 18. But when they do, they're gonna install linux and end up leading SRE teams without a degree in CS.
There are high level patterns, but humans are unique and require different amounts of supervision.
Encourage a healthy relationship with computers and they’ll start doing cool stuff. My son and his buddies are making 3D printed novelties and selling them now!