Some insurers offer "cancel for any reason" (aka CFAR) if purchased within X days of making the initial deposit (usually 14 days or less). That would be your best bet for getting the most back for a claim. But be sure to find out how much is refunded under CFAR as it may not be 100% (usually 70%-75%).
If you have any potential reasons to cancel -- such as you can't request time off yet, elderly relative with health issues, etc. -- be sure to call the insurer and ASK those specific questions to be sure your plan covers it. Covered reasons for cancellation should be covered 100% if you need to make a claim. "Covered" reasons can vary but typically a person on the trip becomes ill and cannot travel, etc. CFAR kicks in for "other" reasons not included as "covered."
Be aware that Concierge deposits are non-refundable, so as soon as you book you have potential for loss. Unlike regular staterooms where nothing is non-refundable until the PIF date. Concierge bookings can be moved to a new date but never refundable.