If you have a table with chairs that have castors; try this to save your carpet. Put the type of plastic floor mats that you use in an office at your desk, under the chairs.
Commercial-type desk floor mats will save your carpet when you have chairs with castors. The wheels over time, will cut into the carpet. You can roll back easily on the mats. This solved a problem for us in our heavily used eating area in a family room. We bought them after the carpet was torn!
Wal-Mart carries a cheap one for around $15.00, you have to let it relax and flatten out since it is folded in half! Office supply stores carry much firmer and more expensive mats.