One thing you should consider when using an extension with the iPad charging cable is that the extra resistance caused by the longer charging cord will cause charging times to increase.

Only by a tiny amount as the extra cable will add only a tiny amount of extra resistance.

The quality of the cable can make a difference as well.

People talk about quality of cables but seem to have little understanding about cables. One can get quality cables that are very inexpensive. The best way to ensure getting one is to pay attention to the source of the cable, not the cost and certainly not whether it has gold plating or not. Stay away from eBay since the true source is always known (unless you are buying a name bland item). Monoprice is always a good place to buy cables. AmazonBasic is another. It is not hard to make a good cable that has quality connectors on either end with sound electrical connections along the length and with good insulation. Gold plating and other marketing talk are just ways to extract more money from folks. USB extension cables (as mentioned by another member in this thread) are another good way to go with apple since they use a proprietary connector on the device side. Since all cables are made from good conductors and are not very long (6 ft is not long), the added electrical resistance is a non issue (as long decent connectors and electrical connections are present within the cable).