Leonidas MarousosYacht charter broker, DMA Yachting
Charters here mostly start from Tortola, where the marinas and provisioning are, and some yachts are based across the channel in the USVI. It matters more than it sounds: a USVI-based boat starting a BVI itinerary means clearing customs on arrival, around $65 per person in fees, and a different tax picture; BVI-based boats skip that step.
Starting from another island, Virgin Gorda say, is occasionally possible with a repositioning fee, but with distances this short it rarely buys you anything; the first anchorage is under an hour away wherever you board.
We wrote up the BVI-vs-USVI-based question in detail, because it changes cost and paperwork more than route: BVI-based vs USVI-based yachts.