The Illinois Marriage and Dissolution of Marriage of Act sets out three different types of maintenance: fixed-term, reviewable, and indefinite. Using the Illinois guidelines, there is a basic formula for calculating spousal maintenance.In Illinois there are five main types of alimony or spousal support; temporary, fixedterm, reviewable, permanent, and lumpsum. In Illinois there are five main types of alimony or spousal support; temporary, fixedterm, reviewable, permanent, and lumpsum. Illinois Legal Aid Online provides a guided interview called an Easy Form that will help you fill out the forms. To initiate alimony in Illinois, the petitioning spouse must request it in the petition for dissolution of marriage. Alimony, spousal support and maintenance all refer to the same thing. Understanding how maintenance is calculated in Illinois divorce cases is crucial for both parties involved. These include income levels of both spouses, future employment prospects, and the marital lifestyle. Understanding how maintenance is calculated in Illinois divorce cases is crucial for both parties involved.