Have compressed chip foam underlay installed during carpet installation. Some indentations are difficult to fix because the underlay beneath the carpet cannot spring back once it has been compacted by weight. Compressed chip foam underlay helps the carpet to support the extra weight of the furniture.
Place furniture glides or cups under the legs of the furniture. Although these items may not be visually appealing, they allow the weight of heavy furniture legs to be dispersed over a larger area. Furniture glides or cups also make it easier to move heavy furniture when necessary.
Move the furniture a few inches forward or backward periodically to distribute the weight over a larger area.