I'm trying to calculate the weight of various tasks. I have tasks that are daily, weekly, monthly, yearly. As a task gets closer to due date, I'd like it to be more important. For example, a weekly task that is due in 2 days is more important than a task due in 7 days. To complicate matters, as an example, a monthly task that is 2 days away from being due should be more important than a weekly task that is 2 days away from being due. Also, I'd like some task to be more important than others by nature. By this I mean one task that is daily is inherently more important than another daily task.
This is my first time posting on math.stackexchange (originally from stackoverflow), so please let me know what other information I need to provide. Perhaps I can simplify this idea somehow?