While working in Adobe Illustrator we often need to pick out the value of a parameter in the dialog box or in the panel. It’s long and not comfortable to use a mouse and keyboard for it. There are shortcuts which allow changing the value to one, to ten and even to 0.1…
Up Arrow button increases the number value to one unit.
Down arrow decreases the number value to one unit.
Shift + Up Arrow increases the number value to ten units.
Shift + Down Arrow decreases the number value to ten units.
Ctrl/Cmd + Up Arrow increases the number value to 0.1 units.
Ctrl/Cmd + Down Arrow decreases a number value to 0.1 units.
In order to switch quickly between numeric fields of the panel or the dialog box use the Tab key.
I hope this all will allow you to work quicker and more effectively.