Simplifying Multiple Conditional Formatting Equations

Remove all current rules.

Let's say you have or expect data in rows 2 to 150.

1) Select P2:P150.
P2 should be the active cell in the selection.
On the Home tab of the ribbon, click Conditional Formatting > New Rule...
Select 'Use a formula to determine which cells to format'.
Enter the formula

=AND($P2<>"", $P2<TODAY()-10)

Click Format...
Activate the Fill tab.
Select yellow as fill color.
Click OK, then click OK again.

2) Repeat step 1) but with

=AND($P2<>"", $P2<TODAY()-20)

and red as fill color.

3) Select O2:P150.
O2 should be the active cell in the selection.
On the Home tab of the ribbon, click Conditional Formatting > New Rule...
Select 'Use a formula to determine which cells to format'.
Enter the formula

=$O2="Done"

Click Format...
Activate the Fill tab.
Select light green as fill color.
Click OK, then click OK again.

4) Select A2:Z150.
A2 should be the active cell in the selection.
On the Home tab of the ribbon, click Conditional Formatting > New Rule...
Select 'Use a formula to determine which cells to format'.
Enter the formula

=$O2="Cancelled"

Click Format...
Activate the Fill tab.
Select dark grey as fill color.
Activate the Font tab.
Make sure the Strikethrough check box is selected.
Click OK, then click OK again.