If you make a bill of material, parts list, quantities, etc. to put on your drawing, try using fields and tables to help yourself out. For example, I often need to show acreages for a residential site plan and total them.
The old way: measure the areas, add them up, and enter the text. If they changed, I had to do the same process, again.
New Way: for those areas, use a closed polygon, boundary, region, or hatch. Where you text is for your list, use a FILED, link it to the objects and display that objects area. If the area of the object changes, your text will update. Put these in a table, have the table do the math for you and you are done.
It's a little more complicated than this to set it all up and there are some things to be careful with, but this is a quick tip. It's meant to get you started.
If you have any questions, just comment them here or e-mail.
Happy CADDING!