Vacuuming an oriental rug is very important to maintaining it. especially wool or silk. Every few years - maybe five or longer if its not in a high traffic area- you take it to a specialist for cleaning. I have several really wonderful oriental rugs - all wool and one silk and wool and they get vacuumed regularly and spot cleaned immediately with a rug cleaning product.
One thing to be aware of in cheaper rugs is that a wet spot can cause the warp threads to bleed into the weft and create a large brown stain. That stain can't be removed. Always consult a professional if the rugs are of heirloom quality.
Hope this helps.