It varies by airport, time of day, staff on duty etc.
I go through airports very regularly. Just returned after going through Heathrow, Mexico City, Panama Tocumen...
General situation is that phones can usually be left in a coat pocket or bag, though for almost the first time I was asked to take my phone out of my bag at when departing from Panama Tocumen.
Laptops always have to be out of the case and visible.
iPads and similar full-size tablets are often (but not always) treated like laptops.
Mini-iPads, Kindles and other e-readers are usually treated like phones, but it is not uncommon to be asked to show them.
Then we get on to shoes, belts. Half the time they ask you to remove them and put them through the scanner. Other times they tell you to go through the scanner.
Also, battery packs for topping up phones and so on. If the battery capacity is not marked clearly, then there is a high risk of getting them confiscated. Many security places have an upper limit on capacity of 15,000mAh or so. That's completely random, in my experience.
Finally, small aerosol sprays (such as anti-perspirant). Sometimes they don't even look; other times they will remove it saying all aerosol sprays are dangerous goods.
In China they ask you to remove your umbrella and show it separately.
Long story short - it depends on the airport and level of alert as well as the individuals on duty.