For either, you can just enlarge the widgets to enlarge the click areas.
For spinners, one can often scroll one's mousewheel (or equivalent gesture) with the pointer inside the spinner to rapidly increase or decrease the value contained within.
The best calendar widgets I've seen also permit you to click a part of the widget -say the displayed date- to type in a desired date.
For either, you can just enlarge the widgets to enlarge the click areas.
For spinners, one can often scroll one's mousewheel (or equivalent gesture) with the pointer inside the spinner to rapidly increase or decrease the value contained within.
The best calendar widgets I've seen also permit you to click a part of the widget -say the displayed date- to type in a desired date.