Try to avoid excessive use of arrays, especially arrays of arrays, unless you really are handling data with two or more dimensions. For example, avoid using $array[0][...] to store one set of data such as the names of the months in a year, and $array[1][...] to store another set of loosely related information, such as sales data for each month. From a performance standpoint, it is more efficient to use two arrays such as $array1[...] (storing the names of the months) and $array2[...] (storing the sales data for each month).