Always round calculations results. You will never (or at least it will be extremely difficult) to tie out or reconcile among schedules or analysis totals. It gives you control over number of digits you want to round to.
To round, all of your calculations should be included in the "Round" functions =round(number,num_digits). For example, look at the example below.
Also, I am using round function when I need to show number rounded to thousands:
This is especially usuful in budget development.