Adding description to layer using ArcMap?

This may be quite basic but can't figure it out.

I have a problem when adding a description to a layer (right click layer -> properties -> general: description). When I update the description, then remove the shp and add it again, the description isn't updated. How should I do this to have the updated description saved at the layer's properties? I tried several times with shapefiles and layer files, and it is updated in layer-file properties, but not in shapefile's. I would need the description of a shapefile to be updated because I'm sending shapefiles to another person.

I'm using ArcGIS 10.1 for Desktop.