> Where you must have at least an allowance of 1, for yourself. And why would you want fewer allowances? That results in more withholding, which is an interest free loan to the government.
If you have other income that's not easy to setup withholding on (such as stock related income, a home sale, or rental income), it can be useful to have more withholding from employment income. A benefit is that you are allowed to pretend withholding is evenly distributed over the year, even if it's not, or if it's more beneficial, you can use the actual timeline for withholding, although that takes a lot more effort.
If you have other income that's not easy to setup withholding on (such as stock related income, a home sale, or rental income), it can be useful to have more withholding from employment income. A benefit is that you are allowed to pretend withholding is evenly distributed over the year, even if it's not, or if it's more beneficial, you can use the actual timeline for withholding, although that takes a lot more effort.