I guess this really applies to all dji flight intelligent batteries, not just the Phantom, but I have some questions in regards to charging batteries etc in different scenarios that I don't think are answered in the manuals etc.

The question is when to recharge batteries that are not fully discharged from flight. For example, I fly and the battery comes back at 25%-30% and I think I might fly in the next coming days or week or two. Do I recharge it later that same day and then recharge it again before I fly, or can I wait to charge it before my next flight?

Basically, how long can a battery that is at partial charge from flying stay like that before needing to be charged, whether to fly it again or for purpose of long term storage?

If your battery is between 25% to 65% it fine to just wait till the day of your next flight. Makes no sense to recharge them ahead of time unless your planning to fly again within the next 72 hours. Now if its going to be weeks or months before a planned flight, then a charge somewhere between 45% to 65% is better for long time storage.