This is an excellent question! An estimate is divided into two categories, Hard costs and allowances. An allowance can be anything from a job variable to a selection item, like light fixtures. Selections are going to be things that you will pick out. Since everyone has different preferences, we make it an allowance.
We use our extensive history of previous jobs, combined with our in-depth meetings about your job, to set a dollar amount we think you might spend for this allowance, and if you spend less, you will receive a credit; if you spend more, you pay the difference. Allowances give you the freedom to choose what you feel is best without many constraints.