Oh what a hideous ad. It's not just the background, which is the exact color of the mysterious substance newborns leave in their diapers. It's not just that this man has a badly knotted tie. It's that he's thinking about..."less taxes."
Was he schooled in a barn?
It's "less tax" and "fewer taxes." "Tax" is something you can't divide into individual units.
Taxes can be. There's your property tax. Your sales tax. Your business and occupations tax. Your social security tax. If you're self employed, there's the employer's half of that same tax. If you work from home, you also pay a tax to your city for the privilege. (SPOGG pays a lot of taxes. We don't mind. We consider it patriotic, to paraphrase Joe Biden. We just wish there weren't so many darned forms and deadlines.)
When you're describing a thing that can't be counted individually, such as "tax" or "money," use less. When you're talking "taxes" or something that can be counted (hours, days, cans of soup, dollars), use fewer.
Thanks to Matthew K. for the photo.