Nikulio wrote:
1)May i hand my notebook on knees or legs?
Here is what Apple says.
“ Set up your notebook on a stable work surface that allows for adequate air circulation under and around the computer.
Do not operate your notebook on a pillow or other soft material, as the material can block the airflow vents.
Never place anything over the keyboard when operating the computer. Never push objects into the ventilation openings.”
https://support.apple.com/en-us/HT201640
Nikulio wrote:
2)I use notebook only at home. What will be better:to left it always plug-in and charging or wait until battery will be lower than 20% and than charge?
Keep the computer plugged in whenever possible.
If you keep the computer always plugged in, make sure that at least twice a month
run it on battery until battery charge level drops to about 50-40%.
Please don’t discharge the battery completely. Discharging battery completely will reduce battery health.
For more useful info:
About notebook batteries
Section: Optimizing Battery Life
http://support.apple.com/en-us/HT204054