When the XTick labels are long numbers that overlap, making them hard to read or distinguish from one another, you may need to use XTICKLABEL_ROTATE90 in order to orient the tick labels vertically rather than horizontally.

Example 1: Set the positions of the XTicks and rotate them.

figure;
plot([1960:2004],randn(45,1));
xlim([1960 2004]);
xticklabel_rotate90([1960:2:2004]);
%Set "Property-value" pairs
xticklabel_rotate90([1960:2:2004],'Color','m');

Example 2: Rotate XTickLabels at their current position

XTick = get(gca,'XTick');
xticklabel_rotate90(XTick);