Shereen,
I am glad you never had moth in your rugs. Our workshop is fixing rugs with reparingcost between 2000 - 3000 $ each month just from moth damage. I guess most of these owners though they dont need moth protection in their rugs. Vacuuming the rug ist the minimum you can do to keep your rug in good condition - you are right to point out to use a cleaner that does not damage the rug.
A professional wash is no luxury, it is the minimum hygienic aspect you should do buying a used rug.
We recommend a wash every 3 - 5 years depending on use (Children, pets). After the wash the mothprotection is washed in. Comparing the cost of maintaining and preserving an expensive or valuable rug and the cost of a moth damage repair. it is no big deal to have it done by a pro. Washing a rug yourself is possible, but you will never reach the same outcome a specialized washing facility can, since you do not have the tools and machinery. The same with repairs. The fringes are not fixed with a needle, it is a special knotting technic. Also I would not use bleach or any other chemicals on an old or antique rug, you never know how the colors will react. Also bleach damages the lanolin in the wool. If you want to do "Homework" use a special wool washing product you would use for fine wool clothing. A mild hair shampoo (PH neutral) will do the same job without damaging the wool. The moth alert boxes are a good idea, but it only tells you that there are moth. The pheromon used in the box attracts the male moth - so you know there are moths. But the female moth is the one that lays the eggs into the wool. This is not stopped by the box.
Just to give fredgrower a idea about the costs:
We start at ca. 1,75$ per squarefoot for basic wash, special handwash for silk and antique is up to 3 $ per squarefoot - depending in colors, condittion and materials in the rug, moth protection is ,25$ per squarefoot. The Do Gereh also has different prices. If it takes up to 10 fringes in one knot on a fine rug like this it is 13 $ per ft, if it is extremely fine done (2 fringes per knot) it is 60 $. The expensive version is usually only requested on fine silk (Hereke, super fine qum, pictural). I guess the prices in USA would be not much different im the same work is done.