You may not know ho versatile the Auto-Fill feature is, so we will cover a few examples.  The first row in Ex 1, is probably what many of us are familiar with - highlight two cells of numbers in a row, and drag the bottom right corner of that combined cell to the right - automatically filling in the cells by incrementing the sequence of the first two numbers.  But Auto-Fill works with calendar information too, as shown on line 2, 3 and 4.  Very quick and handy for laying out monthly, quarterly and annual data.  Line 5 is an example you might use for serial numbers, item numbers, or ticket numbers.

But there is more, when you combine the Auto-Fill with the Format Painter.

We frequently shade alternate rows in large tables to make the data easier to read.  By formatting two cells as shown in Ex 2, and picking up their attributes with the Format Painter, you can apply those attributes to the entire table in Ex 1, resulting in the shaded table in Ex 3.

Of course any cell attributes can be picked-up, and applied with the Format Painter.  It's the technique we use to quickly apply font attributes - font type, bold, italic, etc. to large areas of a spreadsheet quickly.

Note that the black border in Ex 1 encloses the two cells used to Auto-Fill the row.  That border and the light gray border in Ex 1, and Ex 3 are only for illustration.  Don't start with borders in your layout, or they will be applied too, since they are cell attributes.

Don't number a large table of rows, or columns again by hand; use the Auto-Fill technique to free your time for more valuable contributions.